Question: Tobias *** his bike on a road for a 2 hr period. On average, he passed a *** *** marker every *** *** during this period. Which of the following was his *** *** for this 2 hr period?  (A) 10 km/hr (B) 15 km/hr (C) 20 km/hr (D) 25 km/h.
E.