D. She alluded to her husbands affair by the use of the word spree.
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.
C) Fortunato will never leave the vaults again
Trust me, I read this entire thing already...earlier in the year (in Elizabethan AND modern English).
A seems like the most logical answer.