假设下列程序在舞台中显示一个面板.如果用户按下字母B键,程序的输出结果是_________?publicclassTest1extendsApplication{@Overridepublicvoidstart(StageprimaryStage){ Panepane=newPane();Scenescene=newScene(pane,200,250);primaryStage.setTitle("MyJavaFX");primaryStage.setScene(scene);primaryStage.show();pane.requestFocus();pane.setOnKeyPressed(e->System.out.print("Keypressed"+e.getCode()+""));pane.setOnKeyTyped(e->System.out.println("Keytyped"+e.getCode()));}publicstaticvoidmain(String[]args){launch(args);}}

A. KeypressedBKeytypedUNDEFINED
B. KeypressedBKeytyped
C. KeytypedUNDEFINED
D. KeypressedB