Answer:
The correct option is option C. relative pronouns
Step-by-step explanation:
Adjective clauses, also known as adjectival or relative clauses, refer to adjectives that come in the form of a clause. they usually follow the pattern:
Relative Pronoun (or Adverb) + Subject + Verb
in addition, among the main characteristics of these type of clauses are: first, they contain a subject and verb. and second, they begin either with a relative pronoun [who, whom, whose, that, or which] or with a relative adverb [when, where, or why].
Bearing in mind the explained above, it could be said that the correct answer is option C. relative pronouns