In which sentence is the underlined verb in the passive voice?

We have been waiting for an hour.

She has been chosen to sing in tonight's concert.

Hank has won first prize in the talent contest.

Noah's little sister is being silly.

She has been chosen to sing in tonight's concert.

Explanation:

In this sentence the verb in the passive voice is has been chosen. The difference between the active and passive voices is that the active voice tells us who or what is doing the action, but the passive voice only says who or what the action is happening to. In the above sentence, we know what she has been chosen to sing, however we have no idea if she was chosen by her mother, a panel of judges, or the school music director.