What is a class variable?

• A. A variable that is defined within the main method only.
• B. A variable that is declared as static within a class.
• C. A variable unique to each instance of a class.
• D. Any variable declared inside a class.

Answer: (B)

A class variable is defined as a variable that is declared as static within a class. This means that the variable is associated with the class itself rather than with any specific instance of the class. As a result, class variables are shared among all instances, meaning that any change to the class variable will reflect across all instances of that class.

When a variable is declared static, it belongs to the class as a whole, and you can access it directly using the class name, without needing to create an instance of the class. This is particularly useful for constants or properties that should not change across different objects but remain consistent throughout the application.

The other options describe different types of variables: one refers to local variables confined to a specific method, another describes instance variables that are unique to each object, and the last option is too broad, as it includes all types of variables declared within a class, not just class variables specifically.