Which two statements are true?()<br /> <img src="https://nimg.ppkao.com/2018-08/zhoulian/2018080114402878660.jpg?sign=2612a365704408b43b6357ac2a8b145f&t=62d30633" />
A、Foo.beta() is a valid invocation of beta().
B、Foo.alpha() is a valid invocation of alpha().
C、Method beta() can directly call method alpha().
D、Method alpha() can directly call method beta().