You should always drive your bus at...

Answer: C — The appropriate speed for road and weather conditions

Driving at the speed limit (A) may not always be appropriate, as road and weather conditions may require a slower speed. Driving slower than the speed limit (B) may be appropriate in some situations, but again, road and weather conditions should be taken into consideration. Driving at the maximum speed allowed for buses (D) is not always recommended, as it may not be safe for the road and weather conditions. It is important to always adjust your driving speed to the appropriate speed for the road and weather conditions (C) to ensure the safety of yourself and others on the road.