将下列哪个代码(A,B,C,D)放入标注的【代码】处导致编译错误? class A{ public float getNum() return 3.0f; } public class B extends A{ 【代码】 } A. public float getNum(){ return 4.0f;} B. public float getNum(){ } C. public float getNum(double d){ } D. public float getNum(float d){ return 4.0f }