Can we inherit multiple classes?

No, multiple inheritances are not supported in .Net. 

How to add the prefix to the ID column with auto increment ID in SQL?

Here, I am taking an example of a Product. We have different types of  products, so I want to generate a new ProductId using a prefix of value like the below:

What is mean by Shadowing?

Shadowing:

The terms "Shadowing", is defined in VB.Net. In C#, this is known as new keyword.

How do you hide base class methods?

Using the new keyword in the derived class, the base class method can be hidden or suppressed. New implementation can be added to the derived class.

What does the keyword "virtual" mean in the method definition?

Ans: The method can be over-ridden.

How method overriding different from overloading?

Overriding different from Overloading:

If we are overriding the method, derived class method behaviour is changed from the base class. In Overloading, method with same name by different signature is used.

SQL Delete Records within a specific range

SQL Delete Query with BETWEEN condition:

Here i want to delete record from table with in specific range.