单项选择题
阅读下面程序
public class Test2______ {
public static void main(String[] args){
Thread t=new Test2();
t. start();
}
public void run(){
System. out. priatln("How are you. ");
}
}
在程序下画线处填入的正确的选项是（）
A．implements Thread
B．extends Runnable
C．implements Runnable
D．extends Thread