When approaching a red light, you must:

Answer: A — Come to a complete stop

When approaching a red light, the correct course of action is to come to a complete stop. This is because red lights signify a stop in traffic flow and it is important to follow traffic laws and signals to ensure the safety of yourself and others on the road. Option B is incorrect as it suggests proceeding through the red light with caution, which can still result in a collision with other vehicles. Option C is also incorrect as it is illegal and dangerous to drive around a red light. Finally, option D is incorrect as sounding your horn is not necessary and may cause confusion or annoyance to other drivers.