[单选题]
A car is moving with a coml4kmr-s3 d 3gnstant speed v arouq epg39x- ivoy;)1mkpnd a level curve. The coefficient of friction between the tires and the road i;k-pveomy 9qg)31 xip s 0.40. What is the minimum 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. $2v^2/g$
