Microsoft 365 Copilot follows Microsoft’s enterprise data governance and privacy principles, which allow users to manage their own conversation history where appropriate. According to Microsoft AI Business Professional guidance, users can review and delete individual Copilot conversation histories directly from their personal account settings without requiring administrative intervention.

Option D is correct because the My Account portal in Microsoft 365 Copilot allows individual users to manage their activity history, including deleting specific conversations. This enables targeted removal of sensitive interactions while retaining other conversation data.

Option A is incorrect because the Copilot app itself does not provide full account-level activity management capabilities. Options B and C are administrative tools used for tenant-wide governance, compliance, retention policies, and eDiscovery. These portals typically require administrative privileges and are not intended for individual user self-service deletion of specific conversations.

Therefore, to delete a single confidential Copilot conversation without affecting other chats and without requiring administrator approval, the correct tool is the My Account portal in Microsoft 365 Copilot.