The correct answer is D. of.
The word “comprises” means “to include or contain as a part or element.” In this sentence, the building is said to include or contain sixty rooms. Therefore, the correct answer is the preposition “of,” which is used to indicate that something is a part of something else.
The other options are incorrect because they do not make sense in the context of the sentence. The word “off” is used to indicate that something is located away from something else. The word “to” is used to indicate that something is moving towards something else. The word “with” is used to indicate that something is associated with something else.
Here are some examples of how the other options could be used in a sentence:
- The building is located off the main road.
- The building is moving to a new location.
- The building is associated with a number of businesses.