The best way to mitigate the risk to IT infrastructure availability is to establish a disaster recovery plan (DRP), because a DRP is a document that defines the procedures and resources needed to restore the IT infrastructure and resume the critical business functions in the event of a disaster or disruption. A DRP helps to minimize the downtime, data loss, and financial impact of a disaster, and ensures the continuity of operations and services. The other options are not the best ways to mitigate the risk to IT infrastructure availability, although they may also be helpful in supporting the DRP. Establishing recovery time objectives (RTOs), maintaining a current list of staff contact details, and maintaining a risk register are examples of planning or monitoring activities that aim to define the requirements, roles, and responsibilities for the disaster recovery process, but they do not address the actual implementation or execution of the DRP. References = CRISC: Certified in Risk & Information Systems Control Sample Questions