I've read this book before!
Both of there lives before where poor and unhealthy but mutual
However after the pearl they lost koyotito after the pearl gave them bad luck where they're house in their village was burned so after that they were still poor but had bad luck which ruined their family , even killed a family member
I would go with nature because thats what it sounds like to me hope this helps<span />
C would have to be the answer