Answer:
1) preparation costs (cleaning, oil, and gasoline costs) for each car received - Number of cars received
After the cars are received, the car dealership needs to determine the preparation costs associated with each car, before being put in display and sold.
2) salespersons' commission of 5% of the sales price for each car sold - Number of cars sold
Each salesperson's obtains a comission, which represents a variable costs for the car dealership, but only after a sale has been made.
3) administrative costs for ordering cars - Number of cars ordered
These are costs are associated with the ordering of the cars. The can range from the wages paid to the workers who order the cars, to tariffs and transporation expenses in case the cars are imported from abroad.