Should be D

B. Increase the DOS Attack Threshold. Increasing the DOS Attack Threshold means that the system will wait until a higher number of connections are queued before activating DoS protection measures like presenting a Captcha. This is likely to improve user experience because fewer legitimate users will be presented with a Captcha under normal traffic conditions, but it still maintains a level of protection against potential DoS attacks. D. Increase the Session Life. Session Life is the duration for which the system remembers a user after displaying alternate content, like a Captcha. Increasing this time means once a user has completed a Captcha, they wouldn't be prompted again for a longer period. While this could reduce the frequency of Captcha challenges for individual users, it wouldn't prevent the initial challenge from occurring, so it might not be the most effective solution if almost every request is being met with a Captcha.

I think D is the best answer

I would take D: https://norz.at/?p=534

B & D seem valid, I would go for B as well. A is most likely wrong, since we do not want to disable the security measure completely

I would suggest answer B because of https://support.citrix.com/article/CTX250221/appqoe-http-dos-protection-enabled-clients-were-not-getting-the-hic-response-challenge

Answer D seems more appropriate - see https://docs.citrix.com/en-us/citrix-adc/current-release/appexpert/appqoe/appqoe-parameters.html