1.What do you mean by Protected Internal accessibility specifier in C#?
Ans: Protected Internal and Potected Friend both are used for the same purpose, i.e. a member marked with one of these two specifiers can be accessed by any class within the same assembly or by a derived class in any other assembly.The only difference netween these two specifiers is that the former is used in C# and the later in VB.NET.

2.What is the difference between Deep Copy and Shallow Copy?

3.What are the differences between an Abstract Class and an Interface?

4.What is Creational design pattern?

5.What is Behavioral design pattern?

6.What is Structural design pattern?

7.How can you create an immutable object in C#?