The chairperson should not have released the Election Commission's report to the public, for the chairperson did not consult any other members of the commission about releasing the report before having it released.
The argument's conclusion can be properly inferred if which one of the following is assumed?
It would have been permissible for the chairperson to release the commission's report to the public only if most other members of the commission had first given their consent.
This establishes a necessary condition for the release to be permissible: most other members of the commission had to give their consent first. ("Only if" introduces a necessary condition.) Since the chairperson didn't consult any member of the commission, no one gave consent. And zero is definitely less than "most."
For example, let's say there are 5 other commission members:
Since the necessary condition for permissibility wasn't met, releasing the report was not permissible. And if it wasn't permissible, the chairperson shouldn't have done it. That's exactly the conclusion.
You might be bothered by the word "most." You might think the argument only needs to assume that consent from at least one member was required, not from most of them. That's a fair thought, but it's applying the wrong standard. This is a Sufficient Assumption question, not a Necessary Assumption question. We don't need the narrowest possible bridge. We just need an answer that, if true, guarantees the conclusion. (A) does that. It's stronger than strictly necessary, but it still works, because the premise (zero members consulted) doesn't meet even this higher threshold.
All of the members of the commission had signed the report prior to its release.
This doesn't include any normative claim about acceptability or permissibility of release. It tells us that all members signed the report before its release, but it says nothing about when releasing a report isn't acceptable. Without a standard for evaluating the chairperson's action, we cannot guarantee the conclusion that the chairperson should not have released the report. (B) plus the premise leaves the same gap that existed before.
The chairperson would not have been justified in releasing the commission's report if any members of the commission had serious reservations about the report's content.
This has the right structure. It establishes a condition under which the chairperson wouldn't have been justified in releasing the report. If we could trigger that condition using the premise, we'd reach the conclusion. The problem is the trigger: if any members had serious reservations about the report's content. The premise says nothing about whether anyone had reservations about the content. It tells us the chairperson didn't consult anyone, not that anyone objected to the report. Maybe every member loved the report. Maybe they had serious concerns. We just don't know. So even with (C) added, we can't tell whether its condition is met, which means we can't use it to guarantee the conclusion.
The chairperson would have been justified in releasing the report only if each of the commission's members would have agreed to its being released had they been consulted.
This is the most tempting wrong answer. Like (A), it uses "only if" to set up a necessary condition for the release to be justified: each member would have agreed to the release had they been consulted. If we could show this condition wasn't met, we'd be able to conclude the release wasn't justified.
But we'd need to show that at least one member would not have agreed. And the premise doesn't tell us that. The premise tells us the chairperson didn't consult anyone. That's a fact about the chairperson's behavior. It tells us nothing about what the other members would have thought if they had been asked. Not asking someone for their opinion doesn't tell you what their opinion would have been. Maybe every member would have enthusiastically agreed to the release if given the chance. Maybe not. The premise is silent on this.
Notice the distinction that makes (A) work but (D) fail. (A)'s necessary condition is about whether members actually gave consent. If you weren't consulted, you couldn't have given consent. That's a straightforward inference. (D)'s condition is about whether members would have agreed. Whether they would have agreed is a question about their mindset, and the premise gives us no window into that.
Some members of the commission would have preferred that the report not be released to the public.
This tells us some members would have preferred no release. Even if some members didn't want the report released, that doesn't establish that releasing it was wrong. Without a standard connecting member preferences to what the chairperson shouldn't do, (E) can't bridge the gap to the conclusion.