Answer:
The answer is B
Step-by-step explanation:
It cannot be A because the bird is not directly eating the producer so therefore non of the consumers eating the grass is being removed
It is B because if the birds were to be removed then the tertiary consumers would be losing part of their diet, hence their energy
It cannot be C because It just does not make sense, if the birds were removed then the secondary consumers energy levels would drop
It cannot b D because of the same explanation as A pretty much.