What does the option Interface leads to DMZ mean?

When configuring the Check Point Gateway network interfaces, you can define the direction as
Internal or External. What does the option Interface leads to DMZ mean?
Exhibit:

A.
Using restricted Gateways, this option automatically turns off the counting of IP Addresses
originating from this interface.
B. Activating this option automatically turns this interface to External.

C.
It defines the DMZ Interface since this information is necessary for Content Control

D.
Select this option to automatically configure Anti-Spoofing to this net.