Answer : 3. "मिर्जापुर"
Explanation :

Indian Standard Time is calculated from the clock tower in Mirzapur nearly exactly on the reference longitude of IST at 82°30'E, within four angular minutes. In 1905, the meridian passing east of Allahabad was declared as a standard time zone for British India and was declared as IST in 1947 for the Dominion of India.