正解:C
Communication is a key factor for the effectiveness of cybersecurity incident response, as it ensures that all relevant parties are informed, coordinated, and aligned on the incident status, impact, actions, and responsibilities. Communication also helps to maintain trust, confidence, and transparency among the stakeholders, such as senior management, business units, customers, regulators, law enforcement, and media. References = CISM Review Manual, 16th Edition, Chapter 5, Section 5.4.2.11