If a service or solution does not meet all of the specified key characteristics, it is said to be not true cloud computing. Which of the following is a validated cloud computing characteristic?

In the context of cloud computing, a validated characteristic that accurately describes true cloud computing is the 'measured system.' This refers to the capability of cloud services to automatically control and optimize resource usage by leveraging a metering capability appropriate to the type of service (e.g., infrastructure, platform, or software) being provided. In a true cloud environment, resource usage is monitored, controlled, and reported, providing transparency for both the provider and the consumer.

The ability to measure system resources ensures that users are only billed for what they actually consume, enhancing the economic efficiency of cloud services. This characteristic is essential for scalability and accountability, allowing providers to allocate resources effectively and users to manage their costs.

Other characteristics, such as broad network access, resource pooling, and on-demand self-service, are also fundamental to cloud computing. However, if one is looking for a validated characteristic of true cloud computing that embodies a crucial aspect of how cloud services operate in terms of operational efficiency and cost management, considering how the system quantifies resource utilization makes 'measured system' particularly vital. The inclusion of measurable metrics is what enables a cloud service to maintain a dynamic and flexible resource environment.