Select the most appropriate option that can be used as a one-word substitute for the given group of words.

A large building or group of buildings used to house soldiers

barracks

The most appropriate option that can be used as a one-word substitute for the given group of words is barracks.

• Dormitory means a large room or building where a number of people sleep, especially students in a boarding school.
• Fort means a fortified place, especially one with high walls and towers, built to defend against attack.
• Quarters means the place where someone lives or is stationed, especially a military base.

The word barracks is the most appropriate because it specifically refers to a large building or group of buildings used to house soldiers. The other words do not have the same connotation of being a place where soldiers live.