Which two statements are true about delegation as an Object-Oriented Design technique?

Which two statements are true about delegation as an Object-Oriented Design technique?

A.
It is applied to a system only at compile time.

B.
It is an essential element of the Singleton pattern.

C.
It allows you to replace Inheritance with composition.

D.
In Java technology, it is always implemented through the use of generics.

E.
It always requires that at least two objects are involved in handling a request.