Each Microsoft Team is backed by a Microsoft 365 Group. The Office 365 Groups activity report provides detailed information on the activity within these groups, including a "Last Activity Date." By filtering this report, an administrator can identify groups (and therefore their associated teams) that have had no activity within a specified timeframe, such as the last 90 days. This report directly addresses the need to find inactive teams by looking at the underlying group's activity status.

A. Teams advisor is a tool for planning and deploying Teams features; it does not provide reports on team inactivity.
C. The Teams user activity report focuses on individual user actions across all teams, not the activity status of a specific team as a whole.
D. The Teams usage report provides aggregate data on active users and channels but is not designed to easily identify specific teams that are completely inactive.

1. Microsoft. (2024). Microsoft 365 reports in the admin center - Microsoft 365 Groups activity. Microsoft Learn. Retrieved from https://learn.microsoft.com/en-us/microsoft-365/admin/activity-reports/microsoft-365-groups-activity. (This document describes the report, its contents, and how it can be used to "see which groups are actively being used").

2. Microsoft. (2023). Microsoft Teams and Microsoft 365 Groups. Microsoft Learn. Retrieved from https://learn.microsoft.com/en-us/microsoftteams/teams-groups-interactivity. (This document explains the relationship between Teams and Microsoft 365 Groups).