The answer would be A.
The question you have to ask is, is it possessive?
Yes it is possessive.
The wing is owned by the bird. Its wing was broken.
It's means it is or it has.
It's would not make sense in this case because you can not put it is or it has into this sentence.
Perseverance, pulling through, showing up and not backing down. It provides the idea of not giving and being there no matter what, typically the person isn’t someone to back down or give up.
Answer:
Mary Edwards Walker dedicated her life to helping people.
Explanation:
In this paragraph, it talks about her providing healthcare (to help people) and her activism (also to help people) and she became a spy (to help her county, and some people)