Which cloud model provides hardware, storage, networking, and virtualization but requires customers to manage the...

Infrastructure as a Service (IaaS) provides the foundational computing components: virtualized hardware, storage, networking, and hypervisor resources. CompTIA A+ explains that customers using IaaS are responsible for installing and maintaining:

The operating system

Applications

Patches, updates, and configurations

This model gives organizations maximum flexibility because they can build custom server environments without purchasing physical hardware.

In contrast:

SaaS (A) provides fully managed applications—users do not manage OS or software.

PaaS (B) provides a development platform and tools but does not allow OS management.

XaaS (D) is a broad term meaning “anything as a service,” not a specific model.

Thus, IaaS is the only model where OS-level control remains with the customer.