All drivers are required to:

Answer: C — Possess a valid driver's license

All drivers are required to possess a valid driver's license as it is a legal document that allows an individual to operate a vehicle on the road. Option A is incorrect because drivers are not always required to drive under the speed limit, as speed limits vary depending on the road and area. Option B is incorrect because there are certain instances where a driver may be allowed to proceed through a red light, such as when making a right turn after coming to a complete stop. Option D is also incorrect, as while it is a good practice to refrain from using hand gestures while driving, it is not a legal requirement. Thus, C is the most correct answer as all drivers are legally required to possess a valid driver's license while operating a vehicle on the road.