Answer:
d. functional
Step-by-step explanation:
A functional manager can be described as a managers whose responsibility is to manage an organizational unit such as a department within an organization.
A manager can be given the responsibility to manager a specific department such as marketing, engineering, IT, or public relations.
The primary role of a functional manager is to be in charge and manage resources in his department, and to also to direct the technical work of people working on a project under his functional area.
Therefore, managers who are responsible for just one organizational activity are known as functional managers. The correct option is d. functional.