在//point x处的哪个声明是合法的? class Person{ private int a; public int change(int m){ return m; } } public class Teacher extends Person{ public int b; public static void main(String args[]) { Person p=new Person(); Teacher t=new Teacher(); int i; //point x; } } A. i=m; B. i=b; C. i=p.a; D. i=p.change(30);