In a stadium an athlete is running on a circular path with uniform speed during a practice session. The angle covered by him during one second is found to be 10° by coach observing him from the centre of the circular track. What would be the measure of angle (in degree) described by the athlete by an observer standing on the circle?

• A. it depends on the exact position of the observer on the circle
• B. 20
• C. 10
• D. 5