The correct answer is A. class variables.
Static variables are variables that are associated with a class, not with an instance of a class. They are declared with the static keyword. Static variables are created when the class is loaded, and they are destroyed when the class is unloaded. They are shared by all instances of the class.
Class variables are sometimes called static variables because they are associated with a class, not with an instance of a class. They are also sometimes called global variables because they are accessible from anywhere in the program.
Functional variables are variables that are associated with a function, not with an instance of a class. They are declared with the local keyword. Functional variables are created when the function is called, and they are destroyed when the function returns. They are not shared by other functions.
Dynamic variables are variables that are created on the heap, not on the stack. They are declared with the new keyword. Dynamic variables are created when they are first used, and they are destroyed when they are no longer needed. They are not shared by other variables.
Auto variables are variables that are created on the stack, and they are destroyed when the function that contains them returns. They are declared without any keyword. Auto variables are the default type of variable in C++.