Concept:The standard meridian of India is a specific longitude line whose local time is adopted as the official time for the entire country to avoid confusion from varying local times. Explanation:India’s standard meridian is 82∘30′ East longitude. This line passes through Mirzapur in Uttar Pradesh. The time at this meridian is called Indian Standard Time (IST) and is used uniformly across all states. Although the local time between Gujarat and Assam differs by about 1 hour 45 minutes, the standard meridian ensures that all clocks in India show the same time. Among the given options, 82∘30′ E is the correct longitude.