The correct answer is: A. within the class definition.
A static data member is a member of a class that is shared by all objects of that class. It is declared with the keyword static. Static data members are initialized once, when the class is first loaded into memory. They can be accessed using the class name, followed by the dot operator, followed by the member name.
For example, the following code defines a class with a static data member:
“`class MyClass {
public:
static int x;
};
int MyClass::x = 10;
“`
The variable x is a static data member of the MyClass class. It is initialized to the value 10. All objects of the MyClass class will share the same value for x.
Option B is incorrect because static data members are not declared outside the class definition. Option C is incorrect because static data members are initialized when the class is first loaded into memory, not when the program is executed. Option D is incorrect because static data members are always given a value.