The properties of image formed for different object distance are listed below:
Concave mirror:
1)u<f----virtual image , enlarged.
2)f,u,2f---Real, inverted, magnified.
3)u>2f----Real, inverted, diminished.
Convex mirror:
for any object distance virtual,errect and enlarged image.

Convex mirrors are used as reflectors in street lights because they are able to spread the light over a wide area.

The temperature in a spherical reflector type solar cooler is raided to more than $500^\circ C $ by concentrating energy at one point by using a concave reflector.

concave mirror focuses a beam of light from infinity at a point

The mirror used in search lights is a concave mirror

All the above mentioned optical objects use  concave mirrors.

Shaving mirrors need to be concave mirrors

The mirror used by dentists to concentrate light on the tooth to be examined is a concave mirror.

$ \bf{Concave\ mirrors} $ are used by dentists because at a short range (object distances less than the focal length of the mirror) they produce enlarged, erect and virtual images. It is useful to have a magnified image of a tooth when repairing cavities, cracks, or other abnormalities.

Hence, the correct answer is OPTION A.

Convex mirrors produces virtual, erect image to cover wider area, so that drives able to see large area.

Concave mirrors help to produce large image helps doctors to examine body parts and also are used to auto mobile mechanics to produce strong parallel beam of light during night. Concave mirrors are used to focus sunlight to produce heat from solar furnaces.

Concave mirrors are used in solar furnaces, because concave mirrors are the only type of mirror that reflects light in toward a single focal point

Concave mirror (converging mirrors) is used to concentrate a parallel light beam incident on it at point i.e its focus.

Except shaving mirror all uses convex mirrors.

Convex mirrors are used in this case.

Convex mirrors help in viewing wider area which is not possible with the help of plane and concave mirror. It helps to look over a wide range and thus is helpful in avoiding accident.

To capture wide area. Convex mirror on widely used in ATM centres.

Spherical mirrors are used as shaving mirror, dentist mirror and reflector in the headlights of the car. Camera, on the other hand, uses convex lens.

Convex mirrors are used widely as reflectors for street light bulbs as it diverges light ray over a wide area.

Concave mirrors provide large images and the purpose of telescope is to view long distance images.

The mirror used is a convex mirror. 
Since it forms virtual and 'diminished' images, the objects appear to be distant in the mirror than they actually are.

Convex mirror give an erect ,virtual,full size image of distant object with a wider field of view. Thus,convex mirrors enables the driver to view much larger area than would be possible with a plane mirror.

The mirror used by E.N.T. specialists is concave mirror. 

In torches, search lights and headlights of vehicles the bulb is placed very near to the focus of the reflector to get a parallel beam of light through which we can see to a longer distance.

We know, magnification(M)$=\dfrac{\text {height  of  image}\ (h _i)}{\text{height  of  object}\ (h _o)}$
If the magnification will be 1 or more than 1, then the height of image will be equal or greater than the height of object. So, only a part of the image will be viewed through the possible aperture of the mirror. This situation will not provide the driver with the detailed idea of motion of vehicles following.
Hence, Magnification produced by a rear view mirror fitted in vehicles is less than one.

A reflecting telescope uses concave mirrors as they produce images similar to the images produced by convex lenses i.e. upright and smaller than the object.

The magic lantern used a concave mirror in back of a light source to direct as much of the light as possible through a small rectangular sheet of glass.

Concave mirrors project a beam of light outward, which is required in a cinema projector.

Concave mirror forms an image of the sun at a distance of 12 cm.
So the focal length of mirror is 12 cm.
Radius of mirror is $f \times 2=24cm$
For shaving we need to get a virtual image which should be magnified and erect.
So the mirror must be kept at a reasonable distance of 8-10 cm which is within focus and pole.
As the radius is 24cm the object placed at center forms image at the same place
Options $B,C$ are correct.

Concave mirrors are used in telescope to reflect light.

A torch has a bulb working on a battery. A bulb spreads its light rays in all directions. Thus it always diverges.

The concave mirror is used by the dentist as the image formed by the concave mirror when placed between pole and focus is magnified and erect and it provides a clear image to repair tooth cavities.