In SD-WAN priority mode (Manual mode) with a link-cost-factor configured, FortiOS evaluates the specified metric (packet loss) to choose the best link. With the link-cost-threshold set to 0, any member with the lowest packet loss is preferred. Currently, HUB1-VPN1 has the lowest packet loss (2%). If all three members experience the exact same packet loss, a tie occurs. The algorithm then applies the tie-breaker mechanism seen in the output (Tie break: cfg), reverting to the explicitly configured priority-members sequence (6 4 5). Because sequence number 6 (HUB1-VPN3) is listed first in this sequence, it has the highest configuration priority and will be chosen as the new preferred member.

Option A: Incorrect because HUB1-VPN1 and HUB1-VPN2 would tie at 4% loss (beating HUB1-VPN3's 12%). HUB1-VPN1 remains preferred over HUB1-VPN2 due to its higher priority ranking in the configuration.

Option B: Incorrect because HUB1-VPN2 would have the lowest packet loss (4%) among the members, making it the preferred member over both HUB1-VPN1 (12%) and HUB1-VPN3 (12%).

Option C: Incorrect because if HUB1-VPN3 achieves 4% loss, HUB1-VPN1 still maintains the absolute lowest packet loss at 2% and thus remains the active preferred member.

Fortinet, "FortiOS 7.2 Administration Guide," SD-WAN Rules, Section: Manual Mode and Link Cost Factor evaluation. (Document ID: FG-OS-7.2-Admin).

Fortinet NSE 7 SD-WAN 7.2 Study Guide, Chapter 4: SD-WAN Rules, section detailing "Tie break: cfg" mechanisms and Priority member sequencing.