Answer:
none of them really make sense
Explanation:
she pluck up the courage to enter the dark room doesn't make sense
she were plucking up the courage to enter the dark room doesn't make sense
she plucking up the courage to enter the dark room doesn't make sense
you could say:
she plucks up the courage
it makes sense but it's present tense
she plucked up the courage makes the most sense but you say you can't choose that?
you could also say she was plucking up the courage (but not she were)
