I believe it would be B, because there are two subjects that the speaker is referring to at the beginning of the sentence; the caterpillar and the leaf. When they use the word "it" in the second half of the sentence it is unclear whether they mean to say if "it" is the leaf or the caterpillar which they are carrying to their brother.
Answer:
c When she blushed, it gradually became more indistinct, and finally vanished amid the triumphant rush of blood that bathed the whole cheek with its brilliant glow.
Explanation:
Hope this helped!
We went out for something to eat, (After) the dance was finished.