What should be the following distance when driving behind another vehicle?

Answer: C — At least 3 seconds

Maintaining a following distance of at least 3 seconds behind another vehicle is crucial for safe driving. This distance provides adequate time to react to sudden stops or changes in traffic conditions. The 3-second rule allows drivers to determine a safe space behind the vehicle in front by picking a fixed point on the road (such as a sign or a tree) and counting the seconds it takes for the rear of the vehicle in front to pass that point. This practice helps ensure that drivers have enough stopping distance to avoid collisions, considering variables like speed, reaction time, and road conditions. A following distance shorter than 3 seconds may not allow enough time to respond to unexpected events, increasing the risk of rear-end collisions. Conversely, a distance longer than this can still be safe as it may provide extra space in conditions where more time is necessary, such as in adverse weather.