This year, Williamsboro High School introduced a peer tutoring program

Can you please help me explain that in these except (weaken) Questions can we choose irrelevant option or just strengthen ones.
Also then why is B and D wrong?

CR "Except" questions tend to present arguments that are more flawed than usual, often with a conclusion that's hastily reached or way too broad in scope. And it's sensible to make this kind of argument--if you're writing an argument that needs to be vulnerable to at least 4 weakeners, it's going to have to be pretty ramshackle. The arguments in these questions will also exhibit a lot of the classic flaws, such as causation vs. correlation and unrepresentative samples, as building flaws like these into the argument will allow for more "out there" weakeners in the answer choices.

Before moving to the answer choices in CR, it's often a good idea to brainstorm a response of your own to the argument. In a normal Weaken question, any new fact that might lead to the opposite/negated conclusion is a good choice. In Weaken EXCEPT questions, of course, these are going to be the answers that we eliminate. So in this case, we'll go into the answers looking to eliminate any choice that helps us to believe that peer tutoring programs don't necessarily do more harm than good. On their surface, answers (A) and (E) do just this, (A) by playing up the good that has come from the program and (E) by showing that at least one peer tutoring program has apparently done more good than harm. Eliminate (A) and (E).



While the correct answer on Weaken EXCEPT questions will sometimes be a strengthener, more often the right answer will indeed be the least relevant of the answer choices. As such, questioning why answers (B) and (D) are wrong here is totally fair: (B) and (D) seem less relevant to the conclusion than (A) and (E). The short answer is that they weaken the argument indirectly. It can also help to bring back the classic flaws noted above (causation and unrepresentative sample) to explain them.

Causation is at the heart of why answer (B) weakens the argument. The argument incorrectly infers a cause-and-effect relationship between the tutoring programs and the lower average scores simply because the lower average scores came after participation in the tutoring program. That's implicit in the conclusion, which cites the tutoring programs as culprit for the harm done to the scores. However, in pointing out that those who didn't participate in the program saw scores decline even more than those who were in the program, answer (B) suggests that perhaps there was another cause for the score decline. After all, if the "control" group (those who didn't get tutuored) is seeing a decline in scores, then it's hard to be sure that the tutoring program harmed those who participated in it. In fact, (B) suggests that the peer tutoring program may have helped those who participated in it, as they saw a smaller decline in their average scores than a comparable group (members of the same class) over the same time period. Essentially, things were going badly for everyone, but the tutoring program made things go less badly for those who participated.

Answer (D) can be explained in a way similar to (B): the decline seen in scores could have been caused by the significantly harder course work assigned at the end of the period rather than by the peer tutoring program. Answer (D) is also fairly emblematic of an unrepresentative-sample answer. Essentially, the grades cited at the beginning and the grades cited at the end came from two significantly different groups of assignments, and as such they can't really give us an accurate picture of anything.

I hope that helps!
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"Enjoined" is a strange word, because it has two meanings (it can mean "urged" or "encouraged", but in legal contexts it means "prohibited") that are almost exact opposites of each other. But I don't think either meaning is intended here -- I imagine the question means to say "enjoyed".

Whether the students enjoyed their tutoring has little to do with the value the tutoring provided, so C seems like a good answer here. Answer A suggests the tutoring helped in some ways, answer B suggests that tutored students did better than non-tutored students, and answer E suggests that these tutoring programs are sometimes helpful (the conclusion is about all peer tutoring programs, not just the Williamsboro one described in the stem, so learning that another tutoring program worked is useful data). So they all weaken the argument.

Answer D is a bit problematic. The stem talks about the "average scores" of students. Standardized tests are scored. Coursework is graded. It's not clear what coursework has to do with "scores", so it's not clear why answer D is even relevant. But even if we assume the question writer was being careless with language, and that "scores" and "grades" mean the same thing, the fact that coursework was more challenging (which is what you'd expect anyway later in the year as students learn more) does not mean the grading was tougher. I'm sure the OA is C here, but we need to introduce quite a few assumptions to rule out D, and I don't think much of the question overall.
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