What is the alternative configuration if this check box was not checked?

Refer to the exhibit.

The Allow Connections From Untrusted IP Addresses option is enabled in the SMTP Server
Configuration. What is the alternative configuration if this check box was not checked?

A.
The Require Authentication From Untrusted IP Addresses check box must be checked.

B.
The VPIM remote users must be added as contacts.

C.
The IP address access list should be configured to explicitly allow IP addresses from remote
connections.

D.
No alternatives are available.