**Core Concept:** Grammar (Relative Clauses). **Analysis:** The sentence requires a relative clause modifying 'market,' which refers to a place. 'Where' (B) is correct as it introduces a clause describing a location's characteristics. 'Which' (A) would require a comma and refer to the entire preceding clause, which is not the case here. 'When' (C) and 'who' (D) are incompatible with the context of a physical market. **Key Clue:** The antecedent 'market' is a place, requiring the relative adverb 'where.' **Common Pitfall:** Misidentifying the antecedent and selecting 'which' for a non-restrictive clause.