The following sentence has been divided into parts. One of them contains an error.
He conceded / a very crucial / point at / his opponent.

Correct option is B

Option (b) contains an error.
Explanation:
· The verb “conceded” means to admit or acknowledge something, especially after denying it earlier.
· It is usually followed by a direct object, and when used with a person, the correct preposition is “to”, not “at.”
✅ Correct phrase:
He conceded a very crucial point to his opponent.
Grammatical rule used:
· Verb + indirect object requires correct preposition.
· Concede + something + to someone is the correct structure.
Grammar Booster:
Always use “to” with verbs like “explain, suggest, concede” when referring to the person:
· He explained the idea to me.
· She conceded the victory to her opponent.