UGC NET Paper 1 GA 2015 Dec Solved Paper

Among the following propositions two are related in such a way that they can both be true although they cannot both be false. Which are those propositions ? Select the correct code
Propositions :
(A) Some priests are cunning.
(B) No priest is cunning.
(C) All priests are cunning.
(D) Some priests are not cunning.