Developing a risk response plan is the best action to address the risk scenarios with high impact and low likelihood of occurrence, because it helps to define and implement the appropriate actions to reduce or eliminate the risk, or to prepare for and recover from the potential consequences. A risk response plan is a document that outlines the strategies and tactics for managing the identified risks, such as avoiding, transferring, mitigating, or accepting the risk. A risk response plan also assigns the roles and responsibilities for the risk owners and stakeholders, and sets the timelines and budgets for the risk response activities. A risk scenario with high impact and low likelihood of occurrence is a rare but severe event that may cause significant disruption or damage to the organization or its objectives, such as a natural disaster, a cyberattack, or a pandemic. Therefore, developing a risk response plan is the best action to address these scenarios, as it helps to minimize the exposure and impact of the risk, and to enhance the resilience and recovery of the organization. Assembling an incident response team, creating a disaster recovery plan (DRP), and initiating a business impact analysis (BIA) are all important actions to perform as part of the risk response plan, but they are not the best action, as they do not cover the whole spectrum of risk response strategies and activities.
References = Risk and Information Systems Control Study Manual, Chapter 3, Section 3.4.2, page 103