Could you please explain why B is correct and not D?
Although B indicates that mayan cities were not inhabited after 900, we cannot infer that the author's assumption about a drought was correct.
They could have abandoned the city for other reasons

D) Talking proves that there was a prolonged drought during that period.

Why is D not the correct answer?

The key to the correct answer for this one is to provide a link between the abandonment of the cities and the time of the drought. Choice B does that by showing a lack of activity after a certain date.

Choice D only shows that were intermittent droughts, but that was already known from the stimulus.

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