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

Only the right answer will accurately describe both the support and conclusion. It will therefore also be the only one that accurately describes the flaw.

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

in all probability, Megatherium was a predator.

[BACKGROUND]. [BACKGROUND]. [SUPPORT]. It has recently been found that [SUPPORT]. Hence, [CONCLUSION].

Just a lot of extra words to say that since most predators have a shorty, most animals with shorties are predators. That’s not how it works though. Just because most people in the room are American doesn’t mean most Americans are in the room.

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

(A) …most mammals with short olecranon processes have not been predators

Boom! This says most Americans are “not” in the room. And it sticks totally to wording used in the passage.

(B) …the only reason predators need to move…

This is not accurate. Just because the passage only gave one reason doesn’t mean it’s assuming there couldn’t be other reasons.

(C) …could have been a successful predator…

There passage never mentioned or referenced whether predators are “successful”.

(D) …extinct mammals were no shorter than those of living mammals are.

There’s no comparison made between extinct and living animals, so this is way outside the scope.

(E) …a longer olecranon process…

…isn’t what we’re talking about here. The argument is only focused on the meaning of a “short” process.

(A) is the correct answer.