Which sentence contains a verb in passive voice?

a.
aren't those my old ice skates?

b.
their apartment was small but very interesting.

c.
was that photograph taken with the digital camera?

d.
those old records may be worth a lot someday.

The answer is C
Passive Voice is when you have: be + verb (past participation)
For instance, was taken, was contained,...
The photograph was taken with the digital camera is a passive voice because an object is a subject in that sentence, and you can not say the object does the action by putting verb in it; therefore, you use was taken 
A photographer took the photo. In this sentence, the photographer is a human that can do the action, so it is active voice