The girl's went out to find what had happen to the other girls' rabbit.
Answer:
The lines are "As for us, we’re quite fortunate. Luckier than millions of people. It’s quiet and safe here, and we’re using our money to buy food. We’re so selfish that we talk about “after the war” and look forward to new clothes and shoes, when actually we should be saving every penny to help others when the war is over, to salvage whatever we can."
B) The daily work continued; nay, it actually increased;
Something that is happening on a consistent basis. It also gives the feeling that it is work to make it persistent. In option B, the statement "daily work" indicates that something is done daily which supports the idea of persistent. The sentence containing the line "The daily work continued; nay, it actually increased" also includes the description "with an astonishing pertinacity." Pertinacity means persistent determination. The brain failing and life slipping away does not show any persistent determination. Also, the statement that she inquired with acute anxiety does not how any persistent determination.