下列程序标注代码(A,B,C,D)中,哪个是错误的? abstract class A{ abstract float getFloat(); //A void f() //B {} } public class B extends A{ private float m=1.0f; //C private float getFloat() //D { return m; } } A. abstract float getFloat(); B. void f(); C. private float m=1.0f; D. private float getFloat()