The involuntary nature of cardiac muscles is the major quality that makes them contract and relax continuously without pausing or without experiencing any fatigue like the rest of the muscles of our body. The parasympathetic nervous system has effects antagonistic to those of the sympathetic nervous system. The parasympathetic stimulation oh cardiac muscles, however, cannot change the involuntary nature of the cardiac musculature.

Angiotensinogen produced by the liver is broken into angiotensin I by renin which us an enzyme produced by the kidney. This angiotensin I is the precursor of angiotensin II which often plays a role in the constriction of glomerular arterioles, increase blood flow and blood pressure. 

A refractory period is a period of time during which an organ or cell is incapable of repeating a particular action. 

Berger waves, also called as $\alpha$-waves are neural oscillations in the frequency range of 7.5-12.5 Hz. $\alpha$-waves are called as Berger waves in the memory of the founder of EEG.
$\alpha$-waves are one type of brain waves detected either by either EEG, electroenccephalography or magnetoencephalography (MEG) and predominantly originate form the occipital lobe during wakeful relaxation with closed eyes.
Thus, the correct answer is option (C), 'Brain'.

Magnetoencephalography or MEG is a non-invasive technique for investigating human brain activity. It allows the measurement of the ongoing brain activity on a millisecond-by-millisecond basis and it shows where in the brain activity is produced. So, it is helpful in shocked patients.
So, the correct answer is option C.

The tenth cranial nerve (X) is the vagus nerve. It is the longest cranial nerve. (Its name means "wanderer"). It supplies most of the organs in the thoracic and abdominal cavities. This nerve also contains motor fibers to the larynx (voice box) and pharynx, and to glands that produce digestive juices and other secretions. The vagus nerve is responsible for such varied tasks as heart rate, gastrointestinal peristalsis, sweating, and quite a few muscle movements in the mouth, including speech. Parasympathetic innervation of the heart is partially controlled by the vagus nerve and is shared by the thoracic ganglia. To be specific, vagal and spinal ganglionic nerves mediate the lowering of the heart rate. 

Heart beat is initiated by the nodal cells of the SA node. It starts the heart beat. The electrical impulse is then carried by the nerves to the AV node and the Purkinje fibres. Thus the nerves help to spread the impulse throughout the heart. Hence the rate and rhythm of heart beat is controlled by the impulses travelling through the nerves.

The cardiac activity is controlled by the sympathetic nervous system through the epinephrine. It fastens the heartbeat and the cardiac output so that more concentration of oxygen can be supplied to the body parts.

The calcium ions are responsible for muscle contraction by generating the action potential in the muscle cells. More influx of calcium ions may contract the heart muscle to a prolonged state of contraction, which will lead to abnormal increase in the heart rate. 

An electroencephalogram (EEG) is a test that measures and records the electrical activity of your brain by using sensors (electrodes). EEG is most often used to diagnose epilepsy, which causes abnormalities in EEG readings. It is also used to diagnose sleep disorders, coma, encephalopathies, and brain death. EEG used to be a first line method of diagnosis for tumors, stroke and other focal brain disorders.

Magnetoencephalography (MEG) is a non-invasive neurophysiological technique that measures the magnetic fields generated by neuronal activity of the brain. The spatial distributions of the magnetic fields are analyzed to localize the sources of the activity within the brain, and the locations of the sources are superimposed on anatomical images, such as MRI, to provide information about both the structure and function of the brain. 

Electroencephalography (EEG) is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain. German physiologist and psychiatrist Hans Berger recorded the first human EEG in 1924. 

Electroconvulsion therapy or ECT is a procedure in which electric currents are passed through the brain, intentionally triggering a brief seizure.
So, the correct answer is option C.

The vasomotor center is a portion of the medulla oblongata, that together with the cardiovascular & respiratory centers regulates blood pressure too.

• The fish heart contains both oxygenate and deoxygenated blood as it has one atrium and one ventricle.
• Closure of A-V valves produces the first heart sound.
• The vascular connection between the digestive tract and the liver is called the hepatic portal system.
• Purkinje fibres are nerve fibres present in the heart wall.

• The medulla oblongata of the brain controls cardiac activities.
• The action of sympathetic nerve fibres increases the heart rate, while that of the parasympathetic nerve fibres decrease it.
• Sensory fibres extend from the receptors present in the walls of the aortic arch, carotid sinuses and vena cava to the cardiovascular centre in the medulla oblongata.

Cardiac activity could be moderated by the autonomous neural system. The action of sympathetic nerve fibres increases the heart rate and the stroke volume, while that of the parasympathetic nerve fibres decrease these.

Thus, the correct answer is 'The sympathetic system stimulates heart rate and stroke volume.'

An electroencephalogram (EEG) is a test that detects electrical activity in the brain using small, flat metal discs (electrodes) attached to scalp. 

Evoked potential studies measure electrical activity in the brain in response to stimulation of sight, sound, or touch. Stimuli delivered to the brain through each of these senses evoke minute electrical signals. These signals travel along the nerves and through the spinal cord to specific regions of the brain and are picked up by electrodes, amplified, and displayed for a doctor to interpret. Evoked potentials studies involve three major tests that measure response to visual, auditory, and electrical stimuli. Evoked potential studies may be used to assess hearing or sight, especially in infants and children, to diagnose disorders of the optic nerve, and to detect tumors or other problems affecting the brain and spinal cord. The tests may also be performed to assess brain function during a coma.

A SQUID (superconducting quantum interference device) is a very sensitive magnetometer used to measure extremely subtle magnetic fields, based on superconducting loops containing Josephson junctions. SQUIDs are sensitive enough to measure fields as low as 5 aT (51018 T) within a few days of averaged measurements. Magnetoencephalography (MEG), uses measurements from an array of SQUIDs to make inferences about neural activity inside brains. Because SQUIDs can operate at acquisition rates much higher than the highest temporal frequency of interest in the signals emitted by the brain (kHz), MEG achieves good temporal resolution.

Reserpine is an indole alkaloid, antipsychotic and antihypertensive drug that has been used for the control of high blood pressure.
Rustom Jal Vakil was the first to pioneer the use of resperine to control hypertension.
Thus, the correct answer is option (A), 'Jal Vakil'.

$\beta$-wave or $\eta$ rhythm is the term used to designate the frequency range of human brain activity between 12.5 and 30 Hz.
Thus, the correct answer is option C.

A permanent record of the electric events occurring during a cardiac cycle made on a graph paper in a wave form called electrocardiogram. The electric events include depolarization and repolarization of the auricles and ventricles bringing about their contraction and relaxation. The instrument used to record hearts electric event is named electrocardiograph.