The correct answer is C. 64.26.151.37.
The study guide explains the FortiGuard flags shown by diagnose debug rating:
D = Default
I = Initial
T = Timing
F = Failedand specifically: “F = The server is down”
So even though 121.111.236.179 has the lowest RTT in the exhibit, it has the F flag, meaning FortiGate considers that server failed/down, so it will not be chosen.
To determine which active server is selected, the FortiOS administration guide states:
“The server list is sorted first by weight. The server with the smallest RTT appears at the top of the list regardless of weight. … Therefore the top position in the list is selected based on RTT while the other positions are based on weight.”
Among the valid, non-failed choices in the exhibit:
64.26.151.37 → RTT 45
209.22.147.36 → RTT 103
96.45.33.65 → RTT 144
208.91.112.194 → RTT 107
The active server with the lowest RTT is 64.26.151.37, so that is the server FortiGate will choose.
So the verified answer is: C.
