In your opinion is it society's responsibility to rectify the harm suffered by a group of people as a result

Absolutely yes, and that's what we humans have been doing through the years. As a example we have the re-construction of jewish communities that were almost extinct by the Nazi Germany or the refugies all over the world who looked for a new home after WW2 and Syrian conflicts.

The thing is that we humans need to coexist with all types of society to maintain such stability of any country: we need the oil from Russians, the fresh food from Latin America, the technology from Japan, etc; and there s such an human reaction when we see suffer or when we see a group of people being harmed/bullied, even if the problem may not involved an individual directly we have empathy and thanks to that we can coexist and live and solve the problems to common interests.

the answer is b: the religion they practice.

here's why:

there were many different native american tribes and those with similar characteristics formed a main tribe or nation. each had its own language, religion and customs.