A CTO requires full control of the infrastructure layer when moving to the cloud. Which service model satisfies this requirement?

IaaS (Infrastructure as a Service) provides the most control over the underlying infrastructure, including virtual machines, storage, networks, and operating systems. This model allows the CTO to manage the infrastructure layer directly, fulfilling the requirement for full control. SaaS (Software as a Service) offers the least control, as users only interact with the application, and the vendor manages all underlying infrastructure and software. PaaS (Platform as a Service) provides a platform for developing, running, and managing applications without the complexity of building and maintaining the infrastructure, but it abstracts away infrastructure control. DaaS (Desktop as a Service) is a specific type of SaaS or IaaS offering focused on virtual desktops, not the general infrastructure layer.