This kind of stories     instructive while stories of that kind       harmful to children.

A．is; seems

B．are; seem

C．is; seem

D．are; seems

子类可重写父类的方法，重写时必须遵循的原则 ( )

A．子类方法访问权限比父类更高

B．子类方法不能产生比父类更多异常

C．选项A、B都是

D．以上都不对