下面的接口定义中哪一种是错误的 A: interfaceUSB{ publicstaticfinalintmyval=1; voidfun();} B: interfaceUSB{intmyval=1;publicabstractvoidfun();} C: interfaceUSB{ private intmyval=1; publicabstractvoidfun();} D: interfaceUSB{publicstaticfinalintmyval=1;publicabstractvoidfun(intx);}