The answer will be C (didn't mean to put the 2 star lol)
Things are compared with other things to:
1. give them a deeper meaning
2. explainations
3. To show similarites
I think it is D. If it’s wrong i am sorry but i think it’s right
She <span>had been working</span> on the project for 2 days before she finished it. So B is the only right one as it's a continuous action before an action with an exact defining past perfect continuous. Also there's a key word "for" that can help us to find out the tense.
