In the following question, a sentence has been given in Active/Passive voice. Out of the four alternatives suggested, select the one which best expresses the same sentence in Passive/Active voice. We have kept the bird in the cage too long.

• Keeping of the bird in the cage has been done by us for too long.
• The bird has been kept in the cage by us for too long.
• We have been keeping for long the bird in the cage.
• The bird would have been kept in the cage by us for too long.