Final answer:
Riding in the center portion of the lane is a safe and recommended practice for motorcycles to increase visibility and prevent sharing the lane with other vehicles. It is not necessary for cars. Therefore, the correct answer is None of these (d).
Step-by-step explanation:
Riding in the center portion of the lane is a safe and recommended practice for motorcycles. It allows riders to increase their visibility to other drivers, as well as gives them more space to maneuver and avoid hazards. This position also prevents other drivers from sharing the lane with the motorcycle, reducing the risk of a collision.
For cars, riding in the center portion of the lane is not necessary. Cars generally stay in their own lane, and there is no need to worry about others entering the lane. Riding in the center portion of the lane is a safe and recommended practice for motorcycles to increase visibility and prevent sharing the lane with other vehicles. It is not necessary for cars. Therefore, the correct answer is None of these (d).