The organizational structure for Dex$-$Mark Inc. includes the following five departments: Accounting, Research and Development, Finance, Marketing, and Production. This is an example of $\_\_\_\_\_\_\_.$

Group of answer choices

D$.$ Geographic Departmentalization

E$.$ Customer Departmentalization

B$.$ Process Departmentalization

A$.$ Product$/$Service Departmentalization

C$.$ Functional Departmentalization