In this question for answer choice B, I did realize line 8 gives us evidence for this choice, but I was unsure of whether “Toltec” = “another ancient American language”. I kept choice because ultimately, it seemed everything else in the choice was very much in line with everything else in the passage, but does this answer choice require a bit of outside knowledge?
You are right, it does seem like outside knowledge. But we can still make some smart deductions and get to the answer.
The clue is in the way ‘Toltec coinages’ is contrasted. The use of the phrase ‘some probably original’ means that the second part of the sentence would have to mean ‘some derived from other languages’.
Another reason why you can’t eliminate B is because of the way it is phrased - ‘at least some Nahuatl expressions’ tells me the question maker who made this, worded it so that it is harder to eliminate.