This is exactly the behavior described of session reliability

In the question it's specified 100 seconds without authentication so I will go for the "B" - Session reliability didn't need a Citrix ADC and is allowed/Configured by default for 180 seconds. Definitively the good answer I think.

SR is the correct answer.

The policy that enables the behavior where the user doesn’t have to reauthenticate after a network interruption is: D. Auto client reconnect Auto client reconnect is designed to automatically resume sessions without requiring users to reauthenticate when there is a network interruption. This policy helps maintain continuity in the user experience during temporary disruptions.

More support for D. In that same policy article I referred to in the last response... "If you use both session reliability and auto client reconnect, the two features work in sequence. Session reliability closes (or disconnects) the user session after the amount of time specified in the session reliability timeout setting. After that, the auto client reconnect settings take effect, attempting to reconnect the user to the disconnected session." "By default, the timeout is set to 180 seconds, or three minutes." The question specifies 4 minutes, which is outside of the default Session Reliability timeout default setting of 3 minutes. Given the question, it *has* to be Auto Client Reconnect.

B. Session Reliability

I think the answer should be C. Session Reliability is only available if you have a Citrix ADC in the infrastructure. This is not mentioned in the question so your connection than is running on ICA and ICA Keep Alive is the policy to configure the allowed timeout.