The defined change strategy is the input that the BA would use as an input into the assessment of risk. The change strategy is the approach that defines how the change will be implemented, managed, and sustained. It includes the scope, objectives, benefits, stakeholders, governance, communication, training, and transition plans of the change initiative. The change strategy provides the context and direction for the business analysis effort, and helps the BA to identify and evaluate the risks that may affect the success of the change. The other options are not the best inputs for the assessment of risk, as they are more relevant for other purposes, such as estimating the value, prioritizing the requirements, or validating the results of the business analysis effort. References: CBAP Handbook, CBAP Study Guide, BABOK Guide