Answer: All labor used exclusively by that department, but only if the labor is applied to the product itself.
Explanation: Process operation is a Manufacturing system that involves the production of products in a continuous flow or pattern. This type of manufacturing involves the use of interconnected sections and units through the use of conveyor belts,chains etc.
Direct labor is a labor that is used specifically for a particular process or activity.
IN A PROCESS OPERATION, THE DIRECT LABOR IS ALL THE LABOR THAT ARE EXCLUSIVELY USED BY THE DEPARTMENT FOR THE PRODUCTION OF THE PRODUCT ITSELF.