The most important thing for a risk practitioner to ensure once a risk action plan has been completed is that the risk owner has validated the outcomes, as this means that the risk owner has confirmed that the risk response has been implemented and that the risk level has been reduced to an acceptable level. The risk owner is the person or entity with the authority and responsibility to manage a particular risk, and they should evaluate the effectiveness and efficiency of the risk action plan, and report any issues or changes. The risk action plan is a document that outlines the specific actions, resources, responsibilities, and timelines for implementing a risk response. The other options are not the most important things for a risk practitioner to ensure once a risk action plan has been completed, although they may be useful or necessary steps. Updating the risk register is a good practice, but it should be done after the risk owner hasvalidated the outcomes and with the consent of the risk owner. Mapping the control objectives to the risk objectives is a part of the risk response design, but it does not measure the actual achievement of the risk objectives. Achieving the requirements is a desired result, but it does not guarantee that the risk owner has validated the outcomes or that the risk level has been reduced to an acceptable level. References = Risk and Information Systems Control Study Manual, Chapter 4: Risk Response, page 146.