To check the impact of a phishing incident in your Microsoft 365 subscription using the Microsoft Defender portal, you should focus on the Incidents, Email & collaboration reports, and Threat Explorer sections.
1. Identify and Analyze the Incident
2. Investigate Email Details and Exposure
3. Review Remediation Status
Reference:
https://learn.microsoft.com/en-us/defender-xdr/investigate-incidents

Explanation:
The correct answer is Data access governance . Microsoft documents that Data access governance reports in the SharePoint admin center help administrators discover overshared or sensitive SharePoint content and assess sharing exposure. More specifically, Microsoft's sharing links activity reports under Data access governance are designed to monitor sharing activity and identify sites where links such as Anyone , People in the organization , and Specific people links have been created. This is the SharePoint admin reporting area Microsoft provides for investigating external sharing patterns and related exposure.
The other listed reports do not fit this requirement. Agent insights is for Copilot/agent usage, App insights is for application-related insights, Change history tracks configuration changes, OneDrive accounts focuses on OneDrive administration, and Site policy comparison compares site settings. None of those is the SharePoint report family intended for identifying externally shared SharePoint content. Based on Microsoft's documentation, the report area you should use is Data access governance .

Explanation:
Box 1: No
Communications Compliance is focused on monitoring communications (Teams chats, Exchange emails, Viva Engage messages), not content stored in SharePoint document libraries. SharePoint content scanning falls under Information Protection/DLP.
Box 2: Yes
By default, usernames are anonymized (replaced with pseudonyms) in Communications Compliance to protect privacy during the review process. Investigators see anonymized identities unless an admin chooses to reveal them.
Box 3: No
Communications Compliance works silently in the background - it does not add any disclaimer or notification to monitored messages. Users are typically notified via policy tips or organizational policies, not inline disclaimers on each message.

No one can use the agent once an administrator has blocked it. An administrative block at the tenant level or for specific users overrides any individual sharing permissions set by the creator.
Impact of an Administrative Block
When an admin blocks a Microsoft 365 Copilot agent, the following rules apply:
Creator (User1): The creator can no longer test or use the agent. While they may still be able to edit the blocked agent's configuration in some environments, they will receive an error message (such as "blocked by the admin") when trying to interact with it.
Shared User (User2): Any user the agent was shared with loses access immediately. The agent will no longer be visible in their "Available" or "Deployed" apps list in interfaces like BizChat or Microsoft 365 Chat.
Permissions Hierarchy: Administrator settings in the Microsoft 365 admin center take precedence over individual user sharing. Even if User1 has correctly shared the agent, it remains unusable if the admin has set the "Agents" access policy to "No users" or excluded these specific users from the allowed group.
Reference:
https://learn.microsoft.com/en-us/copilot/microsoft-365/microsoft-365-copilot-privacy