When a class method is marked with the keyword friend in a .h file,
select one:
a. it will be a compile error if c++ programmers mark that class method with the keyword friend in the class' .cpp file.
b. it will be a run-time error if c++ programmers mark that class method with the keyword friend in the the class' .cpp file.
c. it will be required for c++ programmers to mark that class method with the keyword friend in the class' .cpp file.
d. it will be a link error if c++ programmers mark that class method with the keyword friend in the class' .cpp file.
e. none of the choices here are correct.