How far must you be behind the car in front of you?

Answer: C — At least three car lengths

The correct answer is "at least three car lengths." This is the recommended distance to maintain between you and the car in front of you while driving. Option A, one car length, may not be enough in the case of sudden braking, and option B, as close as possible, can be dangerous and does not allow for enough reaction time. Option D, a few feet, is also too close and can lead to accidents in the event of sudden stops. It is important to maintain enough distance to ensure safe driving and avoid collisions.