Which of the following access specifies is used in a class definition by default?a.Friendb.Privatec.Protectedd.Public

The access specifier that is used in a class definition by default is b. Private.

Here's a step-by-step explanation:

1. In object-oriented programming, access specifiers determine the visibility of variables, functions, and objects. They set the scope to the members (variables, methods etc.) of the class.

2. There are three types of access specifiers: public, private, and protected.

3. Public members are accessible from any part of the program.

4. Protected members are accessible within the same class and also within the subclasses.

5. Private members are only accessible within the same class.

6. If no access specifier is mentioned, the members of a class are considered as private by default.

So, the answer to your question is b. Private.