A risk response action plan is a document that specifies the actions to be taken to address the identified risks, the resources required, the timelines, the owners, and the expected outcomes. The risk response action plan should be aligned with the enterprise's risk appetite and tolerance, and should be approved by the relevant stakeholders. The best way to ensure the implementation of an effective risk response action plan is to assign clear roles and responsibilities to the individuals or groups who will execute the actions, monitor the progress, and report the results. This will help to avoid confusion, ambiguity, duplication, or omission of tasks, and will ensure accountability and ownership of the risk responses. The other options are not as directly related to the implementation of the risk response action plan, although they may be involved in some aspects of it. References = Risk and Information Systems Control Study Manual, 7th Edition, Chapter 3, Section 3.4.1.1, pp. 121-122.

A denial-of-service (DoS) attack is a type of cyberattack that aims to disrupt or disable the normal functioning of a system or network by overwhelming it with excessive traffic or requests.
The chief technology officer (CTO) has decided to accept the risk associated with the potential loss from a DoS attack. This means that the CTO has determined that the cost or effort of implementing or maintaining controls to prevent or reduce the impact of a DoS attack is not justified by the expected benefits or savings, and that the organization is willing to bear the consequences of a DoS attack if it occurs.
The best course of action for the risk practitioner in this situation is to identify key risk indicators (KRIs) for ongoing monitoring. This means that the risk practitioner should define and measure the metrics that provide information about the level of exposure to the DoS attack risk, such as the frequency, duration, or severity of the attacks, the availability, performance, or security of the systems or networks, the customer satisfaction, reputation, or revenue of the organization, etc.
Identifying KRIs for ongoing monitoring helps to track and evaluate the actual results and outcomes of the risk acceptance decision, compare them with the risk appetite and tolerance ofthe organization, identify any deviations or breaches that may require attention or action, and report them to the appropriate parties for decision making or improvement actions.
The references for this answer are:
Risk IT Framework, page 15
Information Technology & Security, page 9
Risk Scenarios Starter Pack, page 7

The most critical factor when designing controls is the involvement of the process owner, who is the person responsible for the performance and outcomes of a business process. The process owner has the best knowledge and understanding of the process objectives, activities, inputs, outputs, resources, and risks. The process owner can provide valuable input and feedback on the design of controls that are relevant, effective, efficient, and aligned with the process goals. The process owner can also ensure that the controls are implemented, monitored, and improved as needed. The involvement of the process owner can also increase the acceptance and ownership of the controls by the process participants and stakeholders. The other options are less critical when designing controls. The involvement of internal audit can provide assurance and advice on the adequacy and effectiveness of the controls, but internal audit is not responsible for the design or implementation of the controls. The quantitative impact of the risk can help to prioritize and justify the controls, but it is not sufficient to determine the appropriate type and level of controls. The identification of key risk indicators can help to monitor and measure the risk and the performance of the controls, but it is not the main driver of the control design. References = Risk IT Framework, ISACA, 2022, p. 181

A deterrent control is a type of control that has been implemented by displaying a poster that reads "Anyone caught taking photographs in the data center may be subject to disciplinary action.", as it aims to discourage or prevent unauthorized or malicious activities by warning the potential perpetrators of the consequences or sanctions. The other options are not the correct types of control, as they are more related to the correction, detection, or prevention of unauthorized or malicious activities, respectively, rather than the deterrence of unauthorized or malicious activities. References = CRISC Review Manual, 7th Edition, page 154.