阅读下列代码片段: class Interest Test ActionListener{ ...... public void actionPerformed(ActionEvent event){ double i nterest =balance*rate/100; balance +=i nterest ; NumberFormat format =NumberFormat .getCurrencyInstance(); Syste m.out .pri nt]b("balance ="+formatter .format(balance)}; } Private double rate ; } 在下画线处,的正确选项是( )。 A.Imple mentation B.Inheritance C.i mple ments D.extends