The hotel is closed for repairs the end of February. until on within by

The hotel is closed for repairs until the end of February.

Explanation:

the word "closed" tells us that the hotel is already closed [it has already happened] (past tense)

Thus, "by" cannot be used as it would mean that the hotel hasnt been closed yet but will be closed when the end of Feb comes.

Using "until" means that the hotel has already been closed but will be opened after Feb comes.

As for the other 2, it simply doesnt make sense.

the answer should be d) he was one of those young thousands who greeted the war with a certain amount of relief, welcoming the liberation from webs of tangled emotion" since it is the best option because it shows his desire to free himself. 

hope this answer you! have a great day.