Which sentence is in the passive voice?
a. Fossils have been found by the local science club.
b. A helicopter flew just above the tower.
c. Spectators are already claiming their seats hours before the event.
d. In the family room, my sister entertained the baby by singing.
The answer is A. Fossils have been found by the local science club. Since the verb, found, is being done to the subject, fossils, it is in the passive voice. The others are in the active voice since the action is being done by the subject.