The key requirements are to enable collaboration using Yammer, SharePoint Online, and Teams (which replaced StaffHub) while minimizing costs. The Microsoft 365 F1 plan (now part of the F3 plan) is specifically designed for firstline workers and is the most cost-effective enterprise subscription that includes all the specified services. The mention of StaffHub is a strong indicator for a firstline worker scenario, as this application was created for that user base before its features were integrated into Microsoft Teams. While E1 and E3 plans also offer these services, they come at a higher price point, which violates the "minimize costs" constraint.

A. E3: This plan is more expensive than F1 and includes features beyond the stated requirements, failing the cost minimization constraint.

B. ProPlus: Now called Microsoft 365 Apps for enterprise, this plan primarily provides Office desktop applications and does not include SharePoint, Yammer, or Teams.

C. E1: While this plan includes the required collaboration services, it is designed for information workers and is more expensive than the F1 plan.

D. Personal: This is a consumer subscription intended for individual use and is not appropriate for a company-wide deployment.

1. Microsoft 365 Documentation: "Microsoft 365 F3 for Frontline Workers". This page details the services included in the frontline worker plans

such as Microsoft Teams

SharePoint

and Yammer

highlighting its purpose to "Empower your frontline workforce" at a low cost point.

2. Microsoft Docs: "Microsoft StaffHub to be retired". This official document states

"We're retiring Microsoft StaffHub on October 1

2019. We're building StaffHub capabilities into Microsoft Teams." This confirms the link between StaffHub functionality and Teams

which is a core component of the F1/F3 plans.

3. Microsoft Learn: "Describe service and licensing options available in Microsoft 365 - MS-900". This learning path explains that Microsoft 365 F-series plans are designed to be a cost-effective option for firstline workers who need access to communication and collaboration tools like Teams and SharePoint.