What must be documented within 90 days after testing a Cyber Security Incident response plan?

The correct choice requires documenting lessons learned from the testing of a Cyber Security Incident Response Plan (CSIRP) within 90 days. This is a critical component of a robust cybersecurity strategy, as it ensures that organizations can evaluate the effectiveness of their response plan. By documenting these lessons, organizations can identify areas for improvement, refine their incident response processes, and enhance their overall security posture.

This practice not only helps in mitigating future risks but also supports continuous improvement in the organization's cybersecurity framework. The requirement to document both the lessons learned and any observations, even if no significant issues were discovered, reinforces the importance of proactive learning and adaptation in cybersecurity management. By doing so, organizations create a record that can inform future training and preparation, ensuring that they are better equipped for potential incidents in the future.

In contrast, the other choices do not align with the requirements for post-testing documentation related to incident response plans, as they do not pertain to immediate learning or response evaluation. Revenue reports, incidents that did not occur, and technology upgrades are not central to the objective of improving incident response capabilities through documented insights gained from testing. Thus, focusing on lessons learned is crucial for reinforcing the effectiveness and readiness of cybersecurity incident responses.