A man on the top of a vertical observation tower observers a car moving at a uniform speed coming directly towards it. If it takes 8 minutes for the angle of depression to change from 30° to 45°, how soon after this will the car reach the observation tower?

• A. min 17 second
• B. 0 min 57 second
• C. 4 min 34 second
• D. 2 min 23 second