Carrillo agrees with this because he believes that the first primate developed around 81.5 million years ago. However, Olsen also agrees! He says that the oldest fossil dates back 55 million years, implying that the first primate was older than 55 million years old

Carrillo certainly agrees that his model is correct. Olson directly states that Carrillo's model is based on “pure speculation,” making it unreliable.

This answer choice is far too broad for either speaker to have a position on. Olson only discusses one fossil, while Carrillo is primarily focused on the results of his model. You have to make a lot of assumptions to make this work.

Olson certainly agrees that his citation is correct. However, Carillo does not challenge or address this at all. Carillo’s discovery and Olson’s citation could both be correct. It is possible that the earliest primate fossil has never been discovered.

Carrillo does not address this statement at all, and it is implied that Olson disagrees. He acknowledges that the oldest fossils discovered “so far” date back 55 million years. He likely believes that there could be older fossils that have yet to be discovered.