Correct answer:
era
Both words comes from the verb ser but the first one stands for the imperfect and the second one stands for the preterite. So we use the word era because it stands for the imperfect because it talks about actions, conditions, or events that occurred frequently or that were in progress in a moment in the past. Therefore, Pedro was tall and handsome in the past. In this way, we can write this sentence as follows:
Pedro era alto y guapo.