i observed that the first and the last statement of the argument is almost the same and is also the conclusion of the argument.
1. the bolded portion is actually helping the conlusion so choice A is out.
2. as we have identified the conclusion , so Choice B is out.
3. Keep it.
4. it is helping rather that undermining the conclusion.
5. it is actually a premise nota conclusion.
so C is the answer.
A seriously maladaptive trait is unlikely to persist in a given
animal population for long, since there is enough genetic
variation in populations that some members will lack the
trait. Those lacking the trait will compete more successfully
for the available resources. Hence these members of the
population survive and reproduce at a higher rate, crowding
out those with the maladaptive trait.
The proposition that those lacking a maladaptive trait will
compete more successfully for the available resources
figures in the argument in which one of the following
(A) It expresses a view that the argument as a whole
is designed to discredit.
(B) It is the argument's main conclusion.
(C) It is a premise of the argument.
(D) It presents evidence that the argument attempts
(E) It is an intermediate conclusion of the argument.
You can treat this as a bold face CR.