which of\nthe sentences\nbelow uses the\nimperfect tense?\nestaban muy aliviados.\nestar muy…

Brief Explanations:

The imperfect tense of the verb estar (to be) for the third-person plural is "estaban". "Estar" is the infinitive form, and "estuvieron" is the preterite (simple past) tense of estar for third-person plural.

Answer:

Estaban muy aliviados.