Which of the following sentences is most likely written in passive voice?

Jo will have been standing at the corner for an hour.

Meg was found to be the better behaved of the four.

Amy did become a bit unmanageable.

Beth has ridden in the carriage many times.

The correct answer is Meg was found to be the better behaved of the four.

Explanation:

The passive voice is used to emphasize the action. That is to say, it does not matter so much WHO performed the act, but WHAT act was performed.

To form the passive voice it is necessary to use the subject + auxiliary verb (to be) + past participle.

In this case:

Meg was found to be the better behaved of the four.

(subject) (aux. verb) (past participle).

Jow will have been standing at the corner for an hour