If a truck is trying to pass you, you can help the truck driver by

Answer: D — Keeping to the far side of your lane and reducing your speed slightly

When a truck is trying to pass you, it is important to remember that trucks have larger blind spots compared to other vehicles. The correct answer is to keep to the far side of your lane and reduce your speed slightly (option D). By doing this, you are allowing the truck driver more space and visibility to pass you safely. It is crucial to be considerate and cooperative when sharing the road with larger vehicles like trucks.