A truck rounds an unbanked curve of radius 80 m, where the coefficients of static and kinetic friction between the tires and the road are 0.70 and 0.60, respectively. The maximum speed at which the truck can safely negotiate the curve is equal to
A) 78 km/h
B) 100 km/h
C) 56 km/h
D) 23 km/h
E) 84 km
