Final answer:
The imperfect form of the verb 'era' in the sentence is correct. It describes the state of the captain in the past.
Step-by-step explanation:
The imperfect form of the verb in the sentence is correct as written. The verb 'era' is the imperfect form of the verb 'ser', which means 'to be'. In this sentence, it is used to describe the state or condition of the captain, indicating that he was the happiest. The imperfect tense is used to talk about ongoing or habitual actions in the past.
Learn more about Imperfect tense in Spanish