Which word correctly completes the sentence?

as we approached the station, i was startled by a loud blast of the whistle.

a.
trains'

b.
trains

c.
train's

which word correctly completes the sentence?

as our team shouted, the voices echoed throughout the stadium.

a.
players

b.
players'

c.
player's

which word correctly completes the sentence?

we applauded the three skillful performances.

a.
juggler's

b.
jugglers'

c.
jugglers