Concept:A collective noun names a group of people, animals, or things taken as one unit.
Explanation:First, check each option to see if it refers to a group.
Brood means a group of young birds born together – it is a collective noun.
Choir means a group of singers – it is a collective noun.
Caravan means a group of travelers moving together – it is a collective noun.
Courage means the ability to face danger or difficulty – it is an abstract noun, not a group name.
Since courage does not represent any collection, it is not a collective noun.
Answer:Option D: Courage