有如下程序:
#include ＜iostream＞
using namespace std;
class Baseprivate:
char c;
public:
Base(char n):c(n)
～Base()

cout＜＜c;

;
class Derived: public Baseprivate:
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