能将程序补充完整的选项是( )。
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 arg[])

Person p = new Person();
Teacher t = new Teacher();
int i;
______

A．i=m

B．i=b

C．i=p.a

D．i=p. change(50)