单项选择题

有以下程序: #include <iostream> using namespace std; class R { public: R(int f1,int r2) { R1=r1; R2=r2; } void print(); void print ()const; private: int R1, R2; }; void R: :print() { cout<<R1<<", "<<R2<<end1; } void R: :print() const { cout<<Rl<<", "<<R2<<end1; } int main () { R a(5,4); const R b(20,52); b.print (); return 0; } 执行后的输出结果是

A.5,4
B.20,52
C.0,0
D.4,5