Which statement about referential constraints is true?

A.
A referential constraint can be defined against a catalog table.

B.
A referential constraint can be defined on both tables and views.

C.
A referential constraint is used to enforce a logical rule about values of one or more
columns in one or more tables.

D.
A referential constraint is used to enforce a logical rule about how values in one or more
columns in a table should be referenced in a query.