which sentence has a verb that is in the passive voice based on his cell phone records it was believed to be in the area

THIS sentence (the sentence that you provided) has a verb in the passive voice:

Based on his cell phone records, it was believed  to be in the area.

Explanation:

compare & contrast informative essay/speech

when speaking or writing for the sole purpose of providing information in order to give audience members a good basis for making a decision, you would present an informative speech or essay.   because you wouldn’t want to be persuading the audience by arguing for one type of exercise over the other, you wouldn’t choose a persuasive/argumentative technique.   to fairly, and without bias, present information about the pros and cons of each type exercise, a compare/contrast, informative speech/essay would be the best bet.