What are the available lane positions for a motorcycle rider?

Answer: D — Left, center, right

The available lane positions for a motorcycle rider are the left, center, and right portions of a lane. Options A, B, and C refer to lane positions for cars, not motorcycles. Motorcyclists should avoid riding directly behind a car or in its blind spot, so the best lane position is towards the left or right side of a lane. Riding in the center of a lane may also be unsafe as it increases the chances of being hit by debris or oil patches in the road. Therefore, option D is the most accurate and appropriate answer.