Official Explanation
Answer = (A).
Two things happened at the same time: the Congressman’s approval numbers dropped and he received phone calls about the tax raise. The Congressman claims that these two things aren’t related—in other words, just because they happened at the same time, it does not mean that one caused the other. To strengthen his argument, we need to find evidence of another cause for at least one of these events. (A) gives us that: if all elected officials experienced a drop in approval numbers, there may have been some kind of a scandal, or simply increasing disillusionment with politicians in the area.
Even if the citizens who called had voted for Congressman Jones (B), this doesn’t provide an alternate explanation for either the sinking approval numbers or the increase in phone calls. If they hadn’t voted for him, that might make more sense, but it still wouldn’t strengthen the Congressman’s position.
(C) claims that politicians WOULD correlate the phone calls and the approval numbers, which Congressman Jones is not doing. Therefore, we can see that this might be a weakener, but it’s definitely not a strengthener.
(D) suggests that there is a connection between raising taxes and the number of phone calls he receives, which would weaken Congressman Jones’s argument. Furthermore, it doesn’t account for the lower approval rating, either.
While it doesn’t sound pleasant to live in Congressman Jones’s district and pay such high taxes (E), this doesn’t make it more likely that the approval numbers and phone calls are unrelated, which is Congressman Jones’s position.