Which sentence cannot be changed into passive voice

Which of the following sentences is in passive voice

Select the correct Passive voice from the following :

Pick out the correct passive form of the verb for the given sentence :

They called Manu

Which of the following sentences are in active voice ?

1.                      They sing songs in the assembly
2.                    A notice was sent by the manager
3.                  You gave him your pen.
4.                 He has built a house in his native place.

Choose the appropriate Passive Voice for the following sentence :

They were carrying the injured player off the field.