Final answer:
The imperfect form of the verb in the sentence is correct.
Step-by-step explanation:
The imperfect form of the verb in the sentence "El capitán era el más feliz" is correct. In Spanish, the imperfect tense is used to describe past actions or states that were ongoing or habitual in the past. The verb "era" is the imperfect form of the verb "ser" (to be) and correctly matches the subject "el capitán."
Learn more about Spanish verb conjugation