单选题 阅读下列代码片段
class InterestTest______ActionListener{
……
public void actionPerformed(ActionEvent event){
double interest=balance * rate/100;
balance +=interest;
NumberFormat format=NumberFormat.getCurrencyInstance();
System.out.print]b('balance='+formatter.format(balance)};
}
Private double rate;
}
在下画线处，应填的正确选项是{{U}} {{/U}}。

• A.Implementation
• B.Inheritance
• C.implements
• D.extends