D. Cloister, the meaning is cloister<span> (from Latin claustrum, "enclosure") is a covered walk, open gallery, or open arcade running along the walls of buildings and forming a quadrangle or garth.</span>
Here is the sentence using the words capacity and regulation:
The capacity of the hall can only accommodate at most 500 people; therefore, strict regulation of the flow of the people going in and out must be observed all the time. Regulation means control or management. Capacity means the amount or size that something can contain. Hope this answer helps.
The answer to the first question is most likely A. It makes the most sense to me. Though, I apologize if I'm incorrect. ^_^
