Once you have passed a vehicle, you should:

Answer: D — Remain in the same lane

After you've passed a vehicle, it's important to maintain your current speed and stay in the same lane. This allows for a smooth transition and prevents any dangerous maneuvers on the road. Choosing options A, B, or C would be incorrect and potentially dangerous. Speeding up could cause you to lose control of your vehicle, slowing down could cause a hazard for the vehicle behind you, and making a left turn could lead to an accident if there is oncoming traffic. Therefore, remaining in the same lane is the safest and most appropriate action to take.