Answer:
The products use different amounts of different processes in different departments
Explanation:
Plant Wide overhead rates is basically a single rate that is used to assign to the company's manufacturing overhead costs. This is best used when a company produces single product. On the other hand, if the manufacturing of different products with use of different processes is being done then using plant wide rate (which applies only a single rate) might not be appropriate.
The activities of the diversified products would have a high correlation with regard to the input of overheads. Therefore, the departmental overhead rates are preferred when the products use different amounts of different processes in different departments.