Wrong flaw. This is the cookie-cutter flaw of attacking the source of the argument instead of the argument itself. Contrastingly, the stimulus commits different flaws: it confuses belief for fact and appeals to a false authority.

Based on a belief held by most of the biology professors she has talked to, the author concludes that several governmental social programs are wasteful. This includes the same cookie-cutter flaws as the stimulus:

Belief vs. facts, wherein the author assumes that just because people (some professors) believe something (some governmental social programs are wasteful), that thing is true.
Appealing to authority in an area outside their expertise, wherein the author relies on an expert in one field (professors) to support a conclusion concerning a different field (government).

Wrong flaw. While we can’t validly conclude that quantum mechanics is emerging as the best physical theory based on the information given (what if the very best physicists don’t subscribe to it?), (C) appeals to a relevant authority: physicists, on a matter of physics. Contrastingly, the stimulus appeals to a false authority (physicians on astrology). (C) also doesn’t commit the belief vs. fact flaw: it doesn’t state that quantum mechanics is a fact, but that it’s the most prominent theory.

Wrong flaw. We can’t conclude that most mechanical engineers are vegetarians just because they believe that it’s healthier—maybe they eat meat anyway—but this isn’t the same flaw from the stimulus. The author doesn’t claim that, because mechanical engineers believe vegetarianism is healthier, it’s true that vegetarianism is healthier (that would be analogous to the stimulus’ fact vs. belief and appeal to false authority flaws).

Wrong flaw. (E) doesn’t mistake a belief for a fact or appeal to a false authority, as the stimulus does. Also, (E)’s conclusion is that something is “probably” true, whereas the stimulus concludes that something “has been confirmed.” That makes these arguments structurally distinct.