The project manager should monitor and control secondary and residual risks in the risk register. This will ensure that any new risks identified during the implementation of the risk response plan are captured and managed effectively. Monitoring and controlling risks is a continuous process that helps in identifying, analyzing, and planning for new risks as well as updating the risk register as needed.

 According to the PMI Risk Management Professional (PMI-RMP)® Examination Content Outline, one of the tasks under the domain of Risk Response Planning is to “identify and assess the effectiveness of alternative strategies to reduce threats or enhance opportunities, such as mitigation, transference, avoidance, and acceptance” 1. This implies that the project manager should also consider the potential secondary or residual risks that may arise from implementing the chosen risk response strategy. Secondary risks are new risks that are created as a direct result of implementing a risk response, while residual risks are those that remain after the risk response has been executed 2. Both types of risks should be identified and assessed for their impact and probability, and added to the risk register for further monitoring and control. Therefore, the correct answer is A.