The Surface of the Exit Road Is Horizontal,not Banked

Multiple Choice

The surface of the exit road is horizontal,not banked.(See figure.) If the static friction between the tires and the surface of the road is µs = 0.688 and the maximum speed with which the car can exit the highway safely without sliding is 25.2 m/s,what is the radius of curvature of a highway exit ,r?

A) 157 m
B) 64.7 m
C) 94.1 m
D) 207 m
E) 85.6 m