Classes declared with sealed keyword cannot be used as base class for other classes. They must be instantiated to be used.

= is not a valid operator in C#. The correct sign for division is the forward slash (/).

The protected and public members of a base class can be accessed from the derived class.

This is the ultimate base class of all classes in the .NET Framework. It is the root of the type hierarchy.

There is no such exception as 'ArrayMemoryException' in C#.

To remove an item from a particular index, the correct function is 'RemoveAt(int index)'. 

Since the default value of an int is 0, the default value of all the elements in a numeric array is 0.

A message box is used to displays the specified text in a small window containing one or more buttons.

Form is not a keyword in C#. It represents a visual window or frame that can be used to place user interface controls like buttons, labels or listbox.

Interfaces can contain methods, properties, events, indexers or any combination of those four member types.

A delegate can call more than one methods. A delegate that can have more than one element in its invocation list is known as MultiCast Delegate.

The static constructor should be without parameters. If a static constructor is declared parameterised, the compiler will display an error.

Each thread has a Name property that we can set for the benefit of debugging. We can set the name of a thread only once. Naming a thread has its advantages while debugging an application.

Although the StringBuilder class generally offers better performance than the String class, we should not always replace String with StringBuilder. It depends on whether we want to edit the string during the runtime or not.

ADO.NET is an object-oriented set of libraries that allows you to interact with data sources. It cannot be said as an advantage of CLR.

The initial catalog parameter denotes the name of the database to which we want to connect. For example, in the connection string given below, Sample is the name of the database. Data Source=servername;Intial Catalog=Sample;Integrated Security=true

learn prog is the correct answer because the extraction will begin from the 5^th character, which is 'l' and will extract 10 characters from there. The 10^th character from 'l' is 'g'.

The BitArray class stores a compact array of bit values. These value are boolean in nature storing 0 and 1. Elements in an BitArray are accessed using an integer index which starts from 0. Arraylist represents an ordered collection of an object that can be indexed individually. It is basically an alternative to an array. However, unlike array, you can add and remove items from a list at a specified position using an index.

Since the for loop has no initialisation and condition, the loop will run infinitely. The message 'Hello' will be printed infinite number of times.

Abstraction is an emphasis on the idea, qualities and properties rather than the particulars. It places the emphasis on what an object is or does rather than how it is represented or how it works. Thus, it is the primary means of managing complexity in large programs.

When a class derives it functionality (methods and properties) from another class, it is known as inheritance. The derived class can access all the non-private data and behaviour of the base class.

A long type is a 64-bit signed integer type. It has a large range covering from -923,372,036,854,775,808 to 9,223,372,036,854,775,807.

We can call a function from within another function but we cannot define a function inside another. The functions must be defined independent of each other.

A Dataset represent an in-memory collection of data retrieved from a data source. It can contain records of multiple tables. A Dataset can be used for adding and manipulating records of a table in a disconnected dataset.

A boolean type can store either true or false. The default value of boolean is false.