This question doesn't give the GMAT vibe. It must be from the part of the LSAT universe which is not relevant for GMATers.
Between B, C, and D
B. There is no mention of the food value of carnivores or herbivores in the stimulus -
This is clearly out of scopeC. This is utterly nonsense from the GMAT exam prep perspective - because external knowledge about chickens and Tuna is required -
Chickens are omnivores, but Tunas are carnivores, so if humans shift their diet from C (Omnivores) to T (Carnivores) they will save plant resources (Which the chickens consume) -
Meh, the logic is correct but at what cost.D. There is no mention of the ratio of meat to the plants in a herbivore - even if there is a supposed correlation between the two, it need not be the same magnitude for every animal on the planet. Ex. Elephants vs goats - both are herbivores with great differences in their diets. Also, newborn herbivore babies will have high meat to plant ratio because they would mostly be feeding on their mother's milk -
This is ALSO out of scopeThe winner is C, but with presupposed external knowledge