单项选择题

有如下程序: #include <iostream> using namespace std; class A{ public: A(int i){X=i;} void dispa( ){cout<<x<<’,’;} private: int x; }; class B:public A{ public: B(int i):A(i+10){x=i;} void dispb( ){dispa( );cout<<x<<endl;} private: int x; }; int main( )} B b(2); b.dispb( ); return 0; } 程序的输出结果是

A.10,2
B.12,10
C.12,2
D.2,2