During a power outage, a server with redundant power supplies shuts down despite being connected to a UPS. The technician determines that the UPS has failed and replaces it. The technician then separates the power supplies to connect them to two separate UPSs. Which of the following troubleshooting steps did the technician just accomplish? A. Implement preventive measures B. Establish a plan of action C. Document findings/lessons learned D. Test the theory to determine the cause