Answer:
The Clause in this exercise: We must hire a person WHO HAS A DRIVER'S LICENSE.
Is:
A. adjective clause
Step-by-step explanation:
The reasons behind this answer are: First, adjective clauses are dependant meaning that they can't exist by themselves. They provide detailed information about an independent clause. Second, they start with a relative pronoun. In our case "who" is that one. Third, they are composed of multiple words.