xxxDespite being a carnivore, the diet of the bear is largely vegetarian – fresh leaves,
fruits, berries, nuts, roots, and tubers - and animal carcasses rarely.
A. and animal carcasses rarely.
B. and animal carcasses is rare.
C. with animal carcasses as rare.
D. animal carcasses a rarity. // run on or ..no seperator
E. with animal carcasses a rarity.
we need a noun to make it parallel. its between C and E .. .
I pick E ... ( there is one example in the OG saying 'meat a rarity' ..so I think this is correct form).