When approaching an intersection where the signal lights are not working, you should:

Answer: A — Treat it as an all way stop sign intersection.

When approaching an intersection with non-functioning signal lights, it's important to treat it as an all-way stop sign intersection. This means that all traffic approaching the intersection must come to a complete stop and yield the right of way to other vehicles in the intersection. Option B is incorrect because simply waiting until the intersection is clear does not ensure that other vehicles will do the same. Option C is also incorrect because parking the car and directing traffic yourself is not only illegal, but also potentially dangerous. Option D is incorrect because while it is important to slow down and proceed with caution, treating the intersection as an all-way stop is still the safest course of action.