I highlighted C and E as possible answers, but went with E since I took a problem with the fish pass to be the same thing as the dam impeding the fish, i.e. "Since migratory fish have enough water to swim upstream and are not being impeded, there must be nothing wrong with the fish pass.". The answer choice actually stating the opposite of the conclusion may be a bit too on the nose, and maybe I should have caught on to that, but I nevertheless feel that the sentence can be understood
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