类Test定义如下，将下列哪个方法插入③行处是不合法的 ( )
①public class Test
②public float Method(float a，float b)
③
④

A．public float Method(float a，float b，float c)

B．public float Method(float c，float d)

C．public int Method(int a，int b)

D．private float Method(int a，int b，int c)