Concept:An adjective clause (or relative clause) modifies a noun or pronoun. It usually begins with a relative pronoun like which, that, who, or where, and has its own subject and verb.
Explanation:Option A: "The group is informed by a recorder that antidotes are hidden in the room." Here, the word "that" acts as a conjunction, not a relative pronoun. The clause "that antidotes are hidden" is a noun clause (object of "informed"), not describing any noun. No adjective clause exists in this sentence.
Option B: "Matthews enters the bathroom, where he is subdued by a masked figure." The clause "where he is subdued" modifies the noun "bathroom". This is an adjective clause.
Option C: "The phone, which was ringing, was in my room." The clause "which was ringing" modifies the noun "phone". This is an adjective clause.
Option D: "The phone was in my room, which was next to my brother's room." The clause "which was next to my brother's room" modifies the noun "room". This is an adjective clause.
Only option A does not contain any clause that describes a noun or pronoun.
Answer:Option A