When should you lightly apply your brakes to flash the brake lights?

The correct choice emphasizes the importance of communication with other drivers while managing your speed safely. Lightly applying the brakes when you are about to exit the road signals to drivers behind you that you are slowing down. This action is particularly crucial as it provides a clear visual cue to those following you, allowing them to prepare for your change in speed and direction.

In scenarios like exiting, the need for caution increases as your vehicle's speed decreases, and other drivers may not anticipate your actions without proper signals. Employing your brake lights in this manner enhances safety by creating a more predictable driving environment for everyone on the road.

Other options might suggest different situations where you could be flashing brake lights. For example, alerting drivers at high speeds or connecting with the vehicle behind you could create confusion rather than clarity, as the intent of the brake lights may not be obvious. In heavy rain, while visibility is reduced, it's typically more advisable to focus on slowing down gradually and ensuring your following distance is safe, rather than simply flashing brake lights.