Consider Two True Propositions That Are Subcontraries

Consider two true propositions that are subcontraries.Can the referents of their subjects be identical?

A) There can be some overlap, but the two sets of referents cannot be entirely identical.
B) All referents in the affirmative proposition are referents in the negative proposition, but some referents in the negative proposition are not referents in the affirmative one.
C) All referents in the negative proposition are referents in the affirmative proposition, but some referents in the affirmative proposition are not referents in the negative one.
D) None of the referents can be identical, since the referents in one proposition belong to the predicate class, and the referents in the other don't.
E) They must be completely identical, since the two propositions must have the same subject in order to be subcontraries.