若有以下程序：
#include ＜iostream＞
using namespace std;
class A

public:

A()A(int i)x1=i;void dispa()cout＜＜"x1="＜＜x1＜＜",";private:
int x1;
;
class B:public Apublic:
B()
B(int i):A(i+10)x2=i;void dispb()dispa();
cout＜＜"x2="＜＜x2＜＜endl;pnvate:
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