Which of the following statements are true?
A: Subclasses must define all the abstract methods that the superclass defines.
B: A class implementing an interface must define all the methods of that interface
C: A class cannot override the super class's constructor
D: It is possible for two classes to be the superclass of each other
E: An interface can implement multiple interfaces
C: A class cannot override the super class's constructor. (Because constructors are not inherited)