Which conclusion is most scientific when linking India's longitudinal extent with time arrangement?

Correct answer: Longitudes change local time, so standard time provides an administrative solution

Option A gives the scientific relationship between longitude and time. Earth rotates through 360 degrees in approximately 24 hours, so a difference of 15 degrees of longitude corresponds roughly to one hour of local solar-time difference. Since India has a substantial east-west extent, sunrise and local time occur earlier in the east than in the west. Using separate local times everywhere would create administrative and communication difficulties. India therefore adopts one standard time based on a selected standard meridian, allowing a common national time. Latitude, coastline and area do not perform this role, so the other options are incorrect.