Which longitude has been termed as standard meridian of India ?

Correct option is B

The correct answer is (b) 82° 30 East.
The standard meridian of India is 82° 30' East. It passes through Mirzapur in Uttar Pradesh. The time of this meridian is taken as the standard time for the whole country. This is known as Indian Standard Time (IST). The Indian government has adopted a single standard time for the whole country. This standard time is based on the longitude of 82° 30' East.
The choice of 82° 30' East as the standard meridian was not arbitrary. This meridian is close to the center of India, and it also passes through a number of important cities, including Mirzapur, Allahabad, and Nagpur. This makes it a convenient location for the standard Meridian.