Indiana law requires you to dim your headlights when following another vehicle from the rear when you are within ____________ feet of another vehicle.

Answer: C — 200 feet

The correct distance mentioned in the Indiana law is 200 feet. Option A is too short a distance and may not give the following driver enough time to react to any sudden changes from the front vehicle. Option B is also slightly short of the required distance. Option D, on the other hand, is too long and may result in excessive glare for the front vehicle, creating a dangerous situation. So, the most appropriate answer is C.