有基类如下：classBASE{private:intx,y;public:BASE(intx,inty){this->x=x;this->y=y;}voidset(intx1,inty1){x=x1;y=y1;}...};设DERIV为BASE的公有派生类，则下列哪个DERIV的构造函数对基类成员的初始化是正确的？ A: DERIV(int x,inty){BASE(x,y);...} B: DERIV(intx1,inty1){x=x1;y=y1;...} C: DERIV(intx,inty):BASE(x,y){...} D: DERIV(intx,inty){set(x1,y1);...}