Explanation/Reference:

Since the probability and impact the risk are both low, it is appropriate to put the risk on the watch list. This allows the risk manager to monitor the risk without expending significant resources on it.
A watch list is a list of low-priority risks that are not actively managed, but are monitored for changes. A watch list can help the risk manager to keep track of the risks that have low probability and low impact, and to reassess them periodically. Putting the risk on the watch list is the most appropriate action for the risk manager, as it allows him or her to document the risk and review it later. Seeking guidance from SMEs, ignoring the risk, or informing the stakeholders are not necessary actions for a low-priority risk, as they would consume time and resources that could be better spent on more critical risks. Reference: PMI Risk Management Professional (PMI-RMP) Examination Content Outline and Specifications1, page 10; A Guide to the Project Management Body of Knowledge (PMBOKGuide) - Sixth Edition, page 406.

The correct answer is B. Organize a stakeholder workshop to discuss the effectiveness of the new security measures.
The response has already been implemented and tested, but executives are concerned about its operational impact. This is now both a stakeholder engagement and risk monitoring issue. A workshop is the best option because it allows the risk manager to present test results, gather executive concerns, discuss trade-offs between security and operational efficiency, and determine whether further adjustments are needed.
Why the other options are incorrect:
* A. Facilitate a risk identification session on security measures with the company executives. This is too narrow and steps backward. The issue is not only identification, but discussion of effectiveness and operational impact after implementation.
* C. Implement additional security measures to address the concerns expressed by the executives.
Adding controls immediately without analysis may worsen the operational burden.
* D. Acknowledge the concerns and focus on monitoring the effectiveness of the new security measures. Monitoring is important, but this response is too passive given active executive concern.
Engagement and discussion are needed.
Reference-aligned basis:
This answer is consistent with risk and stakeholder management practice that implemented responses should be reviewed with affected stakeholders to confirm effectiveness and unintended impacts.
References:
PMI, A Guide to the Project Management Body of Knowledge (PMBOK Guide) , Monitor Risks and Stakeholder Engagement PMI, Practice Standard for Project Risk Management ISO 31000, communication, consultation, and monitoring principles