I think metaphor because it is not something literal but it has meaning behind it.
Answer:
they allow students work at their own pace.
D. Because all the other ones point out twice that the cat was sitting. :)
Come my and the reason these words need to be capitals is because come is the first word in the sentence and because it starts a quotation. my because it is after a comma.you would capitalize and because it starts a quotation
I'd say your answer is D, but I'm not 100% sure.
I hope I helped. :)