What is a key characteristic of a field variable?

• A. A field variable is declared within a method
• B. A field variable is a member of a class
• C. A field variable cannot retain state
• D. A field variable is only accessible within its method

Answer: (B)

A field variable is indeed a member of a class, which is why this choice is the correct answer. In Java, field variables (also known as instance variables or class variables) are declared within a class but outside of any method. This positioning allows them to store the state of an object (for instance variables) or the class itself (for static variables) for the duration of the object’s lifetime or the class’s lifetime, respectively.

Since field variables are associated with a class, they provide a way for objects of that class to maintain their own unique data and state, making them essential for object-oriented programming. This characteristic of being class members allows object instances to access and modify their fields, providing a mechanism for encapsulation and state management.

The other statements do not accurately describe field variables. For example, field variables are not declared within a method (that would describe local variables), they can retain state as long as the object exists, and they have broader accessibility than just within their method, depending on their access modifiers.