Select the correct passive form of the given sentence.
Humayun built a city named Dinpanah in 1533 in Delhi.
1
A city named Dinpanah was built by Humayun in 1533 in Delhi.
2
A city named Dinpanah had been built by Humayun in 1533 in Delhi.
3
A city named Humayun was built by Dinpanah in 1533 in Delhi.
4
A city named Dinpanah was being built by Humayun in 1533 in Delhi.