An organization uses Exchange Online.
You enable mailbox audit logging for all mailboxes.
User1 reports that her mailbox has been accessed by someone else.
You need to determine whether someone other than the mailbox owner has accessed the mailbox.
What should you do?

A.
Run the following Windows PowerShell command:
Search-MailboxAuditLog -Identity User1 -LogonTypes Owner -ShowDetails

B.
In the Exchange Admin Center, navigate to the Auditing section of the Protection page.
Run a non-owner mailbox access report

C.
Run the following Windows PowerShell command:
New-AdminAuditLogSearch -Identity User1 -LogonTypes Owner -ShowDetails

D.
In the Exchange Admin Center, navigate to the Auditing section of the Compliance Management page. Run a non-owner mailbox access report.

Explanation:

https://technet.microsoft.com/en-us/library/jj150575(v=exchg.150).aspx