Which three are true?

Given these facts about Java types in an application: Which three are true?

A.
Type x could be an abstract class or an interface.

B.
Type y must be an interface.

C.
Type y could be an abstract class or an interface.

D.
Type x must be an abstract class.

E.
Type x could implement or extend from Type y.

F.
Type y must be an abstract class.