Which are those propositions? Select the correct code :
Among the following proposition 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.
(1) Some priests are cunning.
(2) No priest is cunning.
(3) All priests are cunning.
(4) Some priests are not cunning.
(a) (1) and (2) (b) (3) and (4) (c) (1) and (3) (d) (1) and (4)