Ravi starts for his school from his house on his cycle at 8:20 a.m. If he runs his cycle at a speed of 10 km/h, he reaches his school 8 minutes late, and if he drives the cycle at a speed of 16 km/h, he reaches his school 10 minutes early. The school starts at:

• A. 8:40 a.m.
• B. 9:40 a.m.
• C. 8:50 a.m.
• D. 9:00 a.m.