B is the answer because the Europeans were immune to the virus and the Indians weren't so they grew very ill which helped the Europeans.
I think it means any good deed you do, no matter how small or big, will always matter and be appreciated somehow. You also might think it doesn’t matter now, but maybe doing a small favor helped you immensely now because that person returned it by doing a huge favor for you.
Answer:
Third one . Manifest Destiny
the answer is, "intimacy versus isolation." hope this helped!