A communication policy between CSPs and clients is a set of rules and guidelines that define how, when, and what information is exchanged between the parties involved in a cloud service relationship. A communication policy can help ensure transparency, accountability, trust, and collaboration between CSPs and clients, as well as improve the quality and efficiency of the cloud service delivery and management. One of the main reasons why there should be an established communication policy between CSPs and clients is to have protocols in place for notifying staff when a cloud outage occurs. A cloud outage is a disruption or interruption of the availability or functionality of a cloud service, which can affect the performance, reliability, and security of the cloud service and its users. A cloud outage can be caused by various factors, suchas hardware failures, software bugs, network issues, human errors, cyberattacks, or natural disasters. A communication policy can help define the roles and responsibilities of the CSPs and clients in the event of a cloud outage, such as who should report, monitor, escalate, resolve, and communicate the outage, and how they should do so. A communication policy can also help specify the communication channels, methods, formats, and frequencies that should be used to inform the relevant staff and stakeholders about the outage, such as email, phone, text, web portal, dashboard, or social media. A communication policy can also help establish the communication standards, expectations, and metrics that should be followed to ensure the accuracy, timeliness, and completeness of the outage information, such as the cause, impact, status, duration, and resolution of the outage. By having protocols in place for notifying staff when a cloud outage occurs, a communication policy can help minimize the negative effects of the outage, such as customer dissatisfaction, revenue loss, reputation damage, or legal liability. A communication policy can also help enhance the positive outcomes of the outage, such as customer loyalty, service improvement, incident learning, or risk mitigation. Therefore, option C is the best explanation of why there should be an established communication policy between CSPs and clients. Option A is incorrect because it does not explain why there should be a communication policy between CSPs and clients, but rather how to secure network traffic for all communications with endpoints on the corporate local area network. Network security is an important aspect of cloud service delivery and management, but it is not the same as communication policy. Option B is incorrect because it does not explain why there should be a communication policy between CSPs and clients, but rather how to ensure all staff know the acceptable guidelines for representing themselves on social media. Social media is one of the possible communication channels that can be used to exchange information between CSPs and clients, but it is not the same as communication policy. Option D is incorrect because it does not explain why there should be a communication policy between CSPs and clients, but rather how to have proper procedures in place for interactions between internal departments and cloud vendors submitting bids for software or service. Cloud vendor selection is an important aspect of cloud service procurement and contracting, but it is not the same as communication policy. References: CompTIA Cloud Essentials+ CLO-002 Study Guide, Chapter 3: Cloud Business Principles, Section 3.5: Cloud Communication and Stakeholder Management, Page 971 and The Importance of Communication in Cloud Computing | Cloud Computing News