If it is 12 noon at IST (82°30′E), what time is it approximately at 97°30′E longitude?

Answer: C. 1:20 PM .co

Official answer key verified. Detailed explanation coming soon.

Source: RRB NTPC Graduate CBT-1 response sheet 18-Jun-2025 Shift-2 (candidate-shared copy of official answer-key viewing) · official-answer-key