What signal must you give when you are about to slow down or stop?

The correct response in this situation is to extend your right arm with the palm turned downwards. This hand signal is a widely recognized gesture used by drivers to indicate their intention to slow down or stop. By extending your arm in this manner, you effectively communicate with other road users, such as drivers behind you, that you are reducing your speed. This is particularly important on roads without traffic lights or in situations where brake lights may not be clearly visible.

The other options do not provide the same level of clarity or recognition. For instance, raising your arm above your head typically signals a turn or lane change, which does not directly convey the action of slowing down. Flashing headlights rapidly can be confusing and is generally used to signal other drivers to alert them to a situation or right-of-way rather than explicitly indicating a slowdown. Tapping your brakes several times can serve as a warning, but it relies on the visibility of brake lights and may not be as effective if there are issues with visibility or distance. Thus, extending your right arm with the palm facing down provides a clear and universally understood signal to other drivers about your intention to slow down or stop.