Simon is riding a bike at 12 km/h away from his friend Keesha. He throws a ball at 5 km/h back to Keesha, who is standing still on the side walk.
How fast would Keesha say the ball is traveling toward her?
A. 5 km/h
B. 7 km/h
C. 12 km/h
D. 17 km/h