单项选择题

有以下程序; #include <iostream> using namespace std; class R { public: R(int r1,int r2) { R1=r1; R2=r2; } void print(); void print () const; private: int R1, R2; }; void R::print () { cout<<R1<<","<<R2<<endl; } void R::print() const { cout<<R1<<", "<<R2<<endl; } 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