A dab of mud (mass 0.1 kg, and sitting 0.25 m from the center) flies off a horizontal spinning wheel when the wheel takes 1 s to complete one circuit. How large is the friction force between the mud and the wheel?
A. 4.0 N B. 1.0 N C. 0.05 N D. 0.25 N E. 2.0 N