单项选择题

若有以下程序: #include <iostream> using namespaces std; class A { public: A(){} A(int i) { x1=i; } void dispa() { cout<<’x1="<<x1<<","; } private: int x1; }; class B: public A { public: B(){} B(int i):A(i+10) { x2=i; } void dispb() { dispa(); cout<<"x2="<<x2<<end1; } private: int x2; }; int main() { B b(2); b.dispb(): return 0; } 程序运行后的输出结果是

A.x1=10,x2=2
B.x1=12,x2=10
C.x1=12,x2=2
D.x1:2,x2=2