Detailed Solution:

The correct answer is “Mirzapur”.

From Gujarat to Arunachal Pradesh, there is a time lag of two hours. Hence, time along the Standard Meridian of India (82°30'E), passing through Mirzapur (in Uttar Pradesh), is taken as the standard time for the whole country. The latitudinal extent influences the duration of day and night as one moves from south to north.