[单选题]
A car is moving withhaoboymmy*b,e a5:h2, n 6qc46u.n th -dw0iu a constant speed v around a level curve. The coefficient of friction between the tires and the road is 0.40. What is the minimum -t.n ui6uwdh0 radius of the curve if the car is to stay on the road?
A. $0.40v^2/g$
B. $v^2/g$
C. $2.5v^2/g$
D. $2v^2/g$
