A variable is _____ A. an item of data B. a memory location whose value can change while the program is running C. a memory location whose value cannot change while the program is running D. None of the above

The correct answer is: B. a memory location whose value can change while the program is running.

A variable is a location in memory that can store a value. The value of a variable can change while the program is running. This is in contrast to a constant, which is a value that cannot be changed.

Option A is incorrect because an item of data is not necessarily a variable. For example, the value of a constant is an item of data, but it is not a variable.

Option C is incorrect because a memory location whose value cannot change while the program is running is a constant, not a variable.

Option D is incorrect because a variable is a memory location whose value can change while the program is running.