下列程序用GridLayout布局管理器将Frame分为1行3列,并放入Button构件,横线处应填入的语句是( )。
import java.awt.*;
public class Test
public static void main (String[] args)
Frame frm=new Frame ("GridLayout");
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frm.add (new Button("Button1"));
frm.add (new Button("Button2"));
frm.add (new Button("Button3"));
frm.setSize (300,300);
frm.setVisible (true);
A.frm.setLayout (GridLayout (1,3));
B.setLayout (new GridLayout(1,3));
C.frm.setLayout (new GridLayout(3,1));
D.frm.setLayout (new GridLayout(1,3));