This tells us that most bills lacking support from even one major party leader have not passed. Our bill is in an even worse position: all major party leaders oppose it, which means it certainly lacks support from even one leader. So our bill falls into the category of bills that, historically, usually don't pass. This strengthens the prediction that the agriculture bill will fail.

This tells us something about bills that didn't pass: most of them lacked support from any member of a major party. But we only know about the leaders of the major parties, not the members. We don't know whether any rank-and-file members of major parties support the agriculture bill. Even setting that aside, (B) describes what's true of bills that failed, not what predicts failure. Knowing that most bills that failed had a certain trait doesn't tell us that bills with that trait are likely to fail.

This tells us what would happen if all major party leaders endorsed the bill. But they don't endorse it. They oppose it. Knowing what would happen in a hypothetical scenario that's the opposite of our actual situation doesn't help us predict what will happen in the actual situation.

We want to know that most bills that haven’t been supported by a major leader haven’t passed. But learning about most bills that have been passed doesn’t help connect the premise to the conclusion.

This is a tempting trap. You might read (E) and think of it like a conditional: "If a bill passes, then it had support from at least one party leader." If that were a true conditional, we could take the contrapositive: "If a bill doesn't have support from at least one party leader, then it won't pass." And since the agriculture bill has no party leader support, we could conclude it won't pass.

But (E) doesn't say all bills that passed had a leader's support. It says most. And "most" statements don't have contrapositives. "Most bills that passed had a leader's support" doesn't tell us anything about the likelihood of passage for bills that don't have a leader's support. Maybe those bills pass at similar rates, or maybe they almost never pass. We just don't know. (A) is stronger because it directly tells us the track record of bills like ours: bills without any party leader support usually don't pass.