Answer: D) Cost per unit
Explanation:
In terms of manufacturing field, where the goods are manufactured, service operation is the process which workers manage and control demand of customers after getting training from operation manager.
Cost per unit is not the factor that acts as differing agent between manufacturing process and service operation because it is a part of the process which is handled by workers .
Other options are incorrect because transportation, contact of customer and resale are the factors that contrast the manufacturing service and service operations.Thus, the correct option is option(D)
