The correct answer is A. passenger mile/km or Ten kilometer.
A passenger mile/km is a unit of measurement used to calculate the distance traveled by a passenger. It is calculated by multiplying the number of passengers by the distance traveled. Ten kilometer is a unit of length equal to 10,000 meters.
The other options are not correct because they do not measure the distance traveled by a passenger. Per km measures the distance traveled, but it does not take into account the number of passengers. Per passenger measures the number of passengers, but it does not take into account the distance traveled. Per stop measures the number of stops made, but it does not take into account the distance traveled or the number of passengers.
Passenger mile/km is a more accurate measure of transportation costs than the other options because it takes into account both the distance traveled and the number of passengers. This is important because transportation costs are often based on the distance traveled. By using passenger mile/km, transportation companies can more accurately calculate their costs and make more informed decisions about how to operate their businesses.