Why is a single standard time adopted in India?

Correct answer: For uniformity of time across the country

India adopts one standard time to maintain uniformity in administration, transport, communication, education, business, and public scheduling, so option A is correct. India has a wide longitudinal extent, and local solar time is earlier in the east than in the west because Earth rotates from west to east. Using separate local times everywhere would create practical confusion. Therefore, the country uses Indian Standard Time based on the 82°30′ E meridian. Option B is false because India has many longitudes. Option C is false because India is geographically large enough for noticeable local-time differences. Option D is absurd because the Sun rises at different local times across the country, not only in Delhi. A single official time is an administrative choice, not a claim that local solar time is identical everywhere.