Refer to the exhibits.

The question asks what must be done first before two existing physical interfaces can be moved into an SD-WAN zone. The exhibit shows firewall policies referencing port1 directly, and FortiOS does not permit firewall policies to continue referring to interfaces after those interfaces become SD-WAN members. Option D is therefore a reasonable practical first action: remove or modify the direct-interface firewall-policy references. However, the screenshot also shows static routes referencing the same interface. Those route references can likewise require adjustment. FortiOS does not establish a universal ordering that says firewall policies must always be modified before static routes; both changes may be required to complete the migration. Thus the single-answer design is ambiguous even though D is the preferred remediation in the previous review. The administrator should perform an interface-reference audit, move firewall policies to the intended SD-WAN zone, recreate appropriate zone-based static routes, and then configure the SD-WAN members. The default virtual-wan-link zone and other user-defined zones need not be deleted merely because an interface changes membership. The FortiOS 7.6 Members and Zones documentation establishes the relevant referencing restriction.

Verification qualification: Both firewall policy references and static-route dependencies may need changes; the mandated first action is ambiguous.