Answer:
A. The boy who wore a green coat carried his sister home.
Step-by-step explanation:
Adjective clauses are those clauses that cannot stand on it's own, meaning they are no complete sentences. They begin with relative pronouns that connects them to the other words they are describing. The sentence:
"The boy wore a green coat. He carried his sister home" talks of the same boy twice, so by using the relative pronoun who, we can make a new sentence.
Option (A) The boy who wore a green coat carried his sister home is the correct answer for the given sentence (the underlines words representing the adjective clause).