Use the Figure to the Right to Answer the Next

Multiple Choice

Use the figure to the right to answer the next problem.
A ball of mass m and radius r is placed next to a step of height ½ r.
-What is the magnitude of the force the contact point c exerts on the ball when the applied force F just lifts the ball off the floor?

A) mg
B) 1.5 mg
C) 1.73 mg
D) 2 mg
E) 2.14 mg