What should be done if a driver realizes they are driving too close to the vehicle ahead?

Answer: C — Increase the following distance to react safely

Increasing the following distance to react safely is the best course of action when a driver realizes they are too close to the vehicle ahead. Maintaining a safe following distance is crucial for avoiding collisions. It allows the driver enough time to react to sudden stops or changes in traffic conditions. The general rule is to keep at least a three-second gap under normal conditions, and even more in adverse weather or heavy traffic scenarios. By increasing the following distance, the driver can better assess the space between their vehicle and the vehicle in front, allowing for appropriate braking time if necessary. This defensive driving technique enhances overall safety for both the driver and others on the road. The other options fail to address the fundamental issue of proximity. Ignoring the situation could lead to a rear-end collision. Shifting into a higher gear does not affect the distance between vehicles and might even lead to diminished control, especially if sudden braking is required. Using the horn to alert the driver in front may unnecessarily distract or startle them, which does not resolve the danger of following too closely.