What steps should you take?

Your company (your-company.com) just acquired a new business (new-company.com) that is running their email on-premises. It is close to their peak season, so any major changes need to be postponed. However, you need to ensure that the users at the new business can receive email addressed to them using your- company.com into their on-premises email server. You need to set up an email routing policy to accomplish this.

What steps should you take?
A . Set up an Outbound Mail Gateway to route all outbound email to the on-premises server.
B . Set up accounts for the new employees, and use mail forwarding rules to send to the on-premises server.
C . Set up an Inbound Mail Gateway to reroute all inbound email to the on-premises server.
D . Set up a Default route with split delivery to route email to the on-premises server.

Answer: D

Explanation:

https://support.google.com/a/answer/2685650?hl=en

"…If you’re migrating to Gmail from a legacy server, use split delivery to test Gmail with a subset of users. During the testing, the MX records for your domain point to Gmail. Users who have been added in the Admin console get messages in their Gmail inboxes. Set up a catch-all routing rule for unregistered users who need to get messages from the legacy mail server."