Aside from volunteering, people can help non-profit organizations by donating.
Poniatowska's work Nadie, nadie, las voces del temblor gives first-person accounts of the 1985 earthquake in la ciudad de mexico.
So, the answers are:
A. by donating
And..
B. the 1985 earthquake in la Ciudad de Mexico
Good luck with your studies, I hope this helps~!