Which of the following would be the most appropriate way to invoke the CalculateAvg( ) method found in the Student class if an object named gradStudent had been instantiated from the class?

public double CalculateAvg( )

a. gradStudent = CalculateAvg( );

b. answer = Student.CalculateAvg( );

c. CalculateAvg( );

d. answer = gradStudent.CalculateAvg( );

e. answer = gradStudent.CalculateAvg(87.2, 90);