If a Certain Car, Going with Speed V₁, Rounds a Level

Multiple Choice

If a certain car, going with speed v₁, rounds a level curve with a radius R₁, it is just on the verge of skidding.If its speed is now doubled, the radius of the tightest curve on the same road that it can round without skidding is:

A) 2R₁
B) 4R₁
C) R₁/2
D) R₁/4
E) R₁