有如下程序: #include 〈iostream〉 using namespace std; class Base { private:char c; public:Base(char n) :c(n) {}~Base ( ){ cout〈〈c;} }; class Derived : public Base { private:char c; public:Derived(char n) :Base(n+1),c(n) { }~Derived (){ cout〈〈c;} }; int main ( ) {Derived obj (’x’);return 0; } 执行上面的程序将输出( )。
A.xy
B.yx
C.x
D.y