若有以下程序:include using namespaces std;class A {public: A(){} A(int i) {x1=i

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