Which of the following defines managed services in cloud computing?

Managed services in cloud computing are characterized by their integration of scaling, availability, and maintenance functionalities within the service itself. This means that when organizations use managed services, they can automatically scale their resources up or down based on demand without needing to manually intervene. It also ensures that the services are highly available, as the service provider typically ensures uptime and performance through robust infrastructure and management practices.

This built-in capability for scaling and availability allows businesses to focus more on their core operations rather than the underlying architecture, thus optimizing resources and delivering better efficiency. The automation in scaling and maintaining the service contributes significantly to lowering operational overhead and minimizing the risk of downtime, which is crucial for businesses that depend on reliable cloud services.

In contrast, the other options describe scenarios that do not align with the essence of managed services. Manual scaling and management undermine the efficiency that managed services aim to provide, while lack of fault tolerance would go against the expectations of reliability in cloud environments. Additionally, the notion of services always being free does not align with most cloud offerings, which are typically billed based on usage, features, or capacities.