Accepting residual risk is the most important responsibility of a risk owner, as it implies that the risk owner is accountable for the risk and its impact on the enterprise’s objectives and operations. Residual risk is the risk that remains after the implementation of controls, and it should be aligned with the risk appetite and tolerance of the enterprise. The risk owner is responsible for implementing the risk response strategies and monitoring the risk status and outcomes, as well as for reporting and escalating the risk issues and incidents. Testing control design, establishing business information criteria, and establishing the risk register are not the most important responsibilities of a risk owner, but rather the tasks or activities that the risk owner may performor delegate as part of the risk management process. References = CRISC Certified in Risk and Information Systems Control – Question218; ISACA Certified in Risk and Information Systems Control (CRISC) Certification Exam Question and Answers, question 218.