正解:B
A tabletop exercise is a simulation of a potential incident scenario that involves the key stakeholders and tests the roles, responsibilities, and procedures of the incident response plan. It is the best way to determine the effectiveness of the plan because it allows the participants to identify and address any gaps, weaknesses, or ambiguities in the plan, as well as to evaluate the communication, coordination, and decision-making processes. A tabletop exercise can also help to raise awareness, enhance skills, and improve teamwork among the incident response team members and other relevant parties.