Which term describes a relative clause not marked by explicit relative pronoun or complementizer?

• A. Reduced relative clause
• B. Relative clause
• C. Nonrestrictive clause
• D. Free relative clause

Answer: (A)

Reduced relative clauses describe a relative clause that omits the explicit relative pronoun and any auxiliary, leaving a participial phrase that still modifies the noun. For example, "The man standing by the door" conveys the same idea as "The man who is standing by the door," but without the relative pronoun. Likewise, "The book written by Twain" corresponds to "The book that was written by Twain." The essential feature is the lack of an explicit marker like who, which, that, or a form like "is/was" introducing the clause—the idea is carried by a participle that attaches to the noun.

This fits the description in the question: a relative clause not marked by an explicit relative pronoun or complementizer. Other terms describe different clause-edge properties—such as a nonrestrictive clause, which involves information set off by commas, or a general relative clause that still uses a relative pronoun—so they don’t capture the omission of the relative marker in the reduced form.