An administrator receives a call from a user who is unable to receive email. After troubleshooting the administrator is able to resolve the issue and verify that user is able to access email again.  Which of the following is the NEXT step that the administrator should take？（）

• A、 Implement preventative measures.
• B、 Close the issue.
• C、 Document the outcome.
• D、 Question other users to make sure they are not having the same issue.