Which cloud model allows clients to run applications without managing the underlying infrastructure?

The correct answer, which focuses on the Platform as a Service (PaaS) model, is appropriate because PaaS enables clients to develop, run, and manage applications without the complexities of building and maintaining the underlying infrastructure. In a PaaS environment, service providers supply a platform that includes hardware, software, and tools needed for application development. This allows developers to focus on coding and deploying applications rather than managing servers, storage, and networking. PaaS is especially beneficial for developers as it often includes services such as database management, application hosting, and development tools to streamline the development process.

In contrast, Infrastructure as a Service (IaaS) requires clients to manage more of the underlying infrastructure, including virtual machines, storage, and networking configurations. Software as a Service (SaaS) provides complete software solutions hosted by a vendor, but it typically does not allow users to customize the underlying application environment. Managed as a Service (MaaS) is less commonly referenced and operates in a different sphere focused on management services rather than application development. Thus, the PaaS model distinctly stands out as the best choice for running applications with minimal infrastructure management.