If the member variables in a base class are private, then

A) the derived class must use any accessor or modifier functions from the base class

B) you must declare them in the derived class also

C) they can be directly accessed or changed in the derived class

D) making them private causes a syntax error

Sol09:

If the member variables in a base class are private, then option A) the derived class must use any accessor or modifier functions from the base class is correct.

Private member variables are not directly accessible from derived classes. They can only be accessed and modified through accessor and modifier functions provided by the base class. This is done to enforce data encapsulation and ensure that the derived class cannot modify the base class's internal state directly.

Option B) you must declare them in the derived class also is not correct, as private member variables are not visible in the derived class and cannot be declared again.

Option C) they can be directly accessed or changed in the derived class is also not correct, as mentioned above.

Option D) making them private causes a syntax error is not correct either. Making member variables private is a common practice in object-oriented programming to restrict access and enforce data encapsulation. It does not cause a syntax error as long as the correct accessor and modifier functions are used.