类Parent、Child定义如下:public class Parent{public float aFun(float a, float b) throws IOException {}}public class Child extends Parent{//第6行}将以下哪种方法插入行6是不合法的
A. float aFun(float a, float b){ }
B. public int aFun(int a, int b)throws Exception{ }
C. public float aFun(float p, float q){ }
D. public int aFun(int a, int b)throws IOException{ }