下列程序的运行结果是13，请为横线处选择合适的程序（）
#include <iostream>
#include <cmath>
using namespace std;
class A {
public:
A(int X = 0, int Y = 0);
A(A &p);
~A();
int GetX() { return X; }
int GetY() { return Y; }
static int countP;
private:
int X, Y;
};
A::A(int X, int Y) {
this->X = X;
this->Y = Y;
}
A::A(A &p) {
X = p.X;
Y = p.Y;
}
A::~A() {
countP--;
}
int A::countP = 0;
int main() {
A D(3, 4), *p;
int *count = &A::countP;
cout << *count;
A E(D);
p = &E;
_____ = A::GetX;
cout << (p->*j)() << endl;
return 0;
} 
