What is the primary purpose of a Boolean variable in programming?

The primary purpose of a Boolean variable in programming is to represent a truth value, which can be either true or false. This characteristic allows Boolean variables to control program logic and flow, making them essential for decision-making processes in code.

In many programming scenarios, Boolean variables serve as conditions in control structures like if-statements and loops, influencing the execution path of the program based on user inputs or other criteria. When set to true or false, these variables can dictate which block of code should be executed, thereby controlling visibility and access within the application, which is closely related to option B.

Other options, such as storing text, dates, or whole numbers, relate to different data types (like strings, date/time types, and integers) and are not the innate function of Boolean variables. Thus, option B captures the essence of how Boolean variables operate within the context of programming.