Under which circumstance would you require a longer stopping distance?

Answer: D — Both A and C

A longer stopping distance is required in both wet conditions and when the vehicle is fully loaded, which is why the choice highlights these two factors. When driving on wet surfaces, the traction between the tires and the road is significantly reduced. This decrease in traction means that the braking system is less effective, resulting in a longer distance needed to bring the vehicle to a stop safely. Similarly, when a vehicle is fully loaded, it has more mass. This increased weight requires more force to slow down or stop, which translates into a longer stopping distance. The dynamics of heavier vehicles necessitate additional space for safe braking. Both of these conditions contribute to the need for increased stopping distance, making this the appropriate answer.