What should you identify?

You have an Exchange Server 2016 organization. The organization contains three Mailbox servers.
The servers are configured as shown in the following table:

You have distribution group named Group1. Group1 contains three members. The members are
configured as shown in the following table.

You discover that when User1 sends email messages to Group1, all of the messages are delivered
to EX02 first. You need to identify why the email messages sent to Group1 are sent to EX02 instead.
What should you identify?

A.
EX02 is configured as an expansion server.

B.
The arbitration mailbox is hosted on EX02.

C.
Site2 has universal group membership caching enabled.

D.
Site2 is configured as a hub site.

Explanation:
https://technet.microsoft.com/en-us/library/aa998825(v=exchg.150).aspx