Correct Option (D):
The Indian mainland's longitudinal extent spans from approximately 68°7′E to 97°25′E.
Arunachal Pradesh is the easternmost state of India. Its easternmost point, Kibithu, is situated close to the 97°25′E longitude.
Gujarat is the westernmost state of India. Its westernmost point, Ghuar Mota in the Kutch district, lies near the 68°7′E longitude.
This significant longitudinal spread results in a time difference of nearly two hours between sunrise in Arunachal Pradesh and Gujarat. However, India uniformly follows Indian Standard Time (IST), which is based on the 82°30′E longitude, for administrative convenience.
Incorrect Options:
Assam, though located in the northeastern region, does not extend as far east as Arunachal Pradesh, which holds the distinction of being the easternmost state.
Rajasthan is a western state, but its westernmost boundary does not reach as far as Gujarat. Gujarat's geographical position makes it the westernmost state of India.