How will the right answer fit in terms of support and conclusion?

Only the right answer will call out a flaw in the argument, by accurately describing the support and/or conclusion.

Highlight the main conclusion in the passage, if there is one:

Swahili culture was, to some extent, influenced by Oromo culture.

Historian: [BACKGROUND]. [SUPPORT], but [SUPPORT]. This indicates that [CONCLUSION].

The word “influenced” in the conclusion signals that the author is claiming cause-and-effect. The Oromo’s influence caused the Swahili to build these tombs, the author is arguing, since no one else they had contact with built them like that. But the author doesn’t mention the order of events at all, so they’re definitely assuming the Oromo built these kinds of structures first. Probably the right answer will call that out.

Map the wording of the answers to the wording of the passage:

(A) …the Oromo people did not use the structures as tombs

Okay, but how the Oromo people used the structures doesn’t tell us if they “influenced” the Swahili. This doesn’t map to the wording of the conclusion at all.

(B) …because one even occurred earlier than another event…

Nope, the author never said that.

(C) …premises that provide strong support for a much broader conclusion

Definitely not. The premises and conclusion are all only about this specific case of the Swahili and the Oromo. And for the record, that would never be a flaw. We love conclusions that don’t overstep the strength of their evidence.

(D) takes for granted that there was no third civilization responsible…

Not quite, although I see a lot of people pick this one. Sure, if there was that “third civilization”, it would weaken the author’s conclusion. But this isn’t a weaken question. Just because the Oromo may not have been the original tomb builders doesn’t mean they didn’t influence the Swahili. That conclusion only says “to some extent”. So no way this info makes the argument “vulnerable to criticism”.

(E) …earlier than the Swahili civilization did

It’s plain common sense that in order to have “influenced” the Swahili, the Oromo had to build these kinds of tombs first. Since the author never actually said that, it’s definitely a flaw.

(E) is the correct answer.