Examine the following class definition: class DateType
{
public:
void Initialize(int, int, int);
int GetYear() const; // returns year
int GetMonth() const; // returns month
int GetDay() const; // returns day
private:
int year;
int month;
int day;
};

Which of the following statements in a client program correctly prints out the day of the variable day1 of type DateType?

a. cout << day1.GetDay;
b. cout << day1.GetDay();
c. cout << GetDay. day1;
d. cout cout << GetDay(day1);
e. The day cannot be printed by a client program.