Remember that optimistic means "hopeful and confident about the future."
Short answer: A
Step-by-step explanation:
A correctly uses the word, describing how the woman stayed hopeful and confident even after losing her job
B&D both use optimistic as if it is a negative term (which it is the complete opposite of!). Your not an optimist if you are always upset and quiet, and you are not optimistic if you are booing and jeering.
C is wrong because it describes the rain having an emotion. If the sentence read something like "The rain seemed optimistic" perhaps it could be considered a form of word play, but the sentence in its literal meaning is very much incorrect.