Each 15° of longitude represents a one-hour time difference.
A. No difference – Incorrect. 15° longitude implies time difference.
B. 1 hour – Correct. The Earth rotates 360° in 24 hours, so 15° equals 1 hour.
C. 2 hours – Incorrect. That would require a 30° difference.
D. 15 hours – Incorrect. That would need 225° difference in longitude.