According to the Fortinet SD-WAN 7.6 Core Administrator Study Guide, Routing and Sessions, page 193, FortiOS supports static routes referencing SD-WAN zones and individual member interfaces. However, duplicate destination routes cannot simultaneously reference a zone and one of its individual member interfaces.
Option A is correct: FortiOS requires the two static routes to have different destination prefixes. When a static route references an SD-WAN zone, FortiGate creates forwarding entries for the members belonging to that zone. Configuring an additional route with the identical destination prefix through an individual member creates a conflicting route definition.
Overlapping destination networks are permitted when their prefixes differ. For example, a zone-based route could reference 10.0.0.0/8, while a member-specific route references 10.2.0.0/16.
Option B is incorrect: Equal administrative distance does not resolve the duplicate-route restriction. ECMP is not a substitute for valid route configuration.
Option C is incorrect: FortiOS supports default static routes (0.0.0.0/0) referencing SD-WAN zones.
Option D is incorrect: SD-WAN members can include physical interfaces, VLAN interfaces, IPsec tunnels, and other supported interface types.
Therefore, the two static routes must have different destination prefixes, although overlapping networks are allowed.
Exact Source References:
Fortinet SD-WAN 7.6 Core Administrator Study Guide, pages 192–193 — Routing and Sessions.
FortiOS 7.6 Administration Guide — Adding a Static Route and SD-WAN Members and Zones.
