Answer choice E is incorrect because we don't know whether the young salmon are in their prime reproductive stages. If anything, the older salmon are probably in their prime reproductive stages. However, that is not what L is trying to say. L is saying we should protect the YOUNG salmon, and protecting them at their prime reproductive stages does not strengthen this argument the most. If you are looking at the two arguments, get rid of trout vs. get rid of shrimp, answer choice A supports getting rid of the shrimp (the non-native species), which is what L's argument is.
Answer choice E is incorrect because we don't know whether the young salmon are in their prime reproductive stages. If anything, the older salmon are probably in their prime reproductive stages. However, that is not what L is trying to say. L is saying we should protect the YOUNG salmon, and protecting them at their prime reproductive stages does not strengthen this argument the most. If you are looking at the two arguments, get rid of trout vs. get rid of shrimp, answer choice A supports getting rid of the shrimp (the non-native species), which is what L's argument is.