I'd like to provide an answer to this question and would appreciate an expert's opinion, if what I've said isn't accurate or needs to be touched up.
This short stimulus provides us with a hypothesis from cognitive psychologists: misidentification by eyewitnesses (I viewed this as the cause) leads to mistaken convictions in criminal trials (viewed this as the effect).
Several things came to mind when I read the hypothesis, the first of which was: how do we know that this is in fact misidentification and that there isn't something else causing the jurors to mistakenly convict (i.e. an ulterior, vindictive motive possibly to harm the person on trial)? The second question that I had was: just how often does an eyewitness's testimony result in a conviction, or even a 'mistaken' conviction for that matter?
Remember, that this is a strengthen EXCEPT question, so the four wrong answers will strengthen the hypothesis by addressing the gaps between the two statements in the cognitive psychologists' claim.
(A) is wrong because it strengthens the notion that it is a common reason for conviction; this addresses the second gap I mentioned above
(B) is wrong because it strengthens the notion that the person on trial has in fact been misidentified by the eyewitness, more often than not as well. This makes it seem more likely that the eyewitness didn't have an ulterior motive and that it was genuinely a case of misidentification.
(C) is wrong for basically the same reason that the previous answer choice was wrong. This makes it seem more likely that the eyewitness didn't have an ulterior motive and that it was genuinely a case of misidentification.
(D) is correct because it seems to weaken the hypothesis slightly, but a subtle assumption needs to be made in order to make this a 'true' weakening type of answer choice. So, if anything, this answer choice is out of scope. I think it weakens by showing that the convictions might not be mistaken because if jurors are instructed by the judge, then it seems less likely that they would mistakenly convict someone. The assumption that I brought up has to do with the fact that the jurors actually listen to the judge's instruction and act according to what they have been told by the judge.
(E) is wrong because it strengthens the hypothesis by providing a reason for why jurors might be more inclined to mistakenly convict someone because of a misidentification provided by a very convincing eyewitness, whom, in actuality, might not have any idea of what they're really talking about.
The only concern that I had was with the wording "common reason" in the hypothesis. Experts, does this mean that we are dealing with a correlation or a cause/effect claim? I was a little torn here, and I thought it was more of a cause/effect claim, so I'd appreciate clarification on this aspect of the question.
Thanks in advance and I hope my analysis was insightful and, for the most part, accurate as well.