Fill in the blank with a suitable preposition:
It will take me _______ an hour to finish this essay.
The preposition ‘under’ is generally used along with a unit of time to denote that an action can be done before the end of a particular time. In other words, it means ‘less than’. In the given context the person can finish the essay in less than an hour, therefore option D is correct. Whereas, ‘from’ is unsuitable here since it is used to denote the beginning of an action which is not the case here. Thus option B is incorrect. On the other hand prepositions ‘through’ and ‘behind’ are unsuitable, because the former is used to speak about a lengthy period- from the beginning to the end, while the latter means to be late. Both of these are inappropriate in the given context, so options A and C are incorrect.