Select the correct passive form of the sentence.
An IIT student has developed an indigenous, low-cost smart home system.
1
An indigenous, low-cost smart home system have been developed by an IIT student.
2
An indigenous, low-cost smart home system had been developed by an IIT student.
3
An IIT student has been developed an indigenous, low-cost smart home system.
4
An indigenous, low-cost smart home system has been developed by an IIT student.