You have a Microsoft 365 tenant that uses Microsoft Office 365 Message Encryption (OME). You need to ensure that any emails containing attachments and sent to user1@contoso.com are encrypted automatically by using OME. What should you do? 

Answer options:

A. From the Exchange admin center, create a new sharing policy.
B. From the Microsoft 365 security center, create a Safe Attachments policy.
C. From the Exchange admin center, create a mail flow rule.
D. From the Microsoft 365 compliance center, configure an auto-apply retention label policy.

C

You can create mail flow rules to help protect email messages you send and receive. You can set up rules to encrypt any outgoing email messages and remove encryption from encrypted messages coming from inside your organization or from replies to encrypted messages sent from your organization. Reference: https://docs.microsoft.com/en-us/microsoft-365/compliance/define-mail-flow-rules-to-encrypt-email?view=o365-worldwide