A.what classes are instantiated from.
B.an instance of a class.
C.a blueprint for creating concrete realization of abstractions.
D.a reference to an attribute.
E.a variable.

A.an implementation of an abstraction.
B.an attribute defining the property of a particular abstraction.
C.a category of objects.
D.an operation defining the behavior for a particular abstraction.
E.a blueprint for making operations.