A circular curve of a highway is designed for traffic moving at 72 km/h. if the radius of the curved path is 100 m, the correct angle of banking of the road should be given by:
A. `tan^(-1).(2)/(3)`
B. `tan^(-1).(3)/(5)`
C. `tan^(-1).(2)/(5)`
D. `tan^(-1).(1)/(4)`