为自己加油

假设已经定义好了类student，现在要定义类derived,它是从student私有派生的，则定义类derived的正确写法是

A.class derived：student private{    //............}
B.class derived：student public {    //............}
C.class derived：public student {    //............}
D.class derived：private student{    //...........}