Choose a right answer
[A]
The object-relational model is the extension of the relation model with new features such as structured types, methods, identifiers for tuples, and references
[B]
Object-relation model allows a non-atomic type that can be a relation schema which is called nested relation
[C]
In object-relational model, the type of an attribute can be a reference to a tuple with a given schema or a set of references to tuples with a given schema
[D]
All of the others
Answer: D