Answer: The verb that is in the passive voice is B) was hired.
Step-by-step explanation: A verb in the passive voice is formed with a finite form of the verb "to be", which acts as the auxiliary verb, and the past participle of a main verb. Therefore, in the sentence provided, the verb that is in the passive voice is "was hired" since it has been formed with "was" (a finite form of the verb "to be") and the past participle of the verb "hire", which is "hired". In contrast, "had graduated" has been conjugated into the Past Perfect and "to teach" represents the full infinitive form of the verb.