Grace works in at an advertising agency. grace's coworkers her complete presentations, contact clients, and assist her with research. her coworkers are serving a(n):

I believe the answer is Instrumental function
Instrumental function refers to the function that focused on aiding or supporting the plan/action of other members within the organization.
For most companies, This type of function usually held by someone in the 'lower hierarchy' of the organization (such as secretary, personal assistant, or intern)