3、下面哪些方法置于指定位置会导致编译错误 public class J_Super { public float getNum(){ return 3.0f; } public class J_Sub extends J_Super{ //指定位置 } }
选项：

A:A public float getNum(){return 4.0f;};
B:B public void getNum(){};
C:C public void getNum(double d){};
D:D public double getNum(float d){return 4.0d; }