Which of the following correctly describes the purpose of global variables?

Global variables are designed to be accessible and editable throughout the entire program, which is why this option is the correct choice. When a variable is declared as global, it exists in the global scope, allowing any function in the program to read and modify its value. This can be particularly useful when you need to share data or maintain state across different functions without passing the variable as an argument.

In contrast, other options highlight limitations that do not apply to global variables. The first choice suggests that global variables can only be accessed within one function, which is not true, as they can be accessed from anywhere in the program. The second choice describes a scenario similar to local variables, where values are only maintained within specific functions, which does not apply to global variables. The last option implies that global variables are restricted to the setup phase, which misrepresents their nature, as they persist throughout the program’s execution rather than being confined to a specific part.