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( )。

A．Implementation

B．Inheritance

C．implements

D．extends