Q. (16-20) : Each of the following sentences contains a blank space. Below the sentences are a set of words lettered (a) through (d). Select the word that best completes the sentence.
16. Doctoral students who are preparing to take their qualifying examinations have been studying in the library night--------the last three months.[NCC Bank MTO-2011 : 2011]
[NCC Bank MTO-2011 : 2011]
[NCC Bank MTO-2011 : 2011]