Which of the following best describes IaaS?

Infrastructure as a Service (IaaS) is characterized by the provision of hardware resources over the internet. This model allows users to rent virtualized computing resources, such as virtual machines, storage, and networks, from a cloud provider rather than investing in physical hardware. IaaS provides the foundational building blocks for creating and managing a cloud-based infrastructure, which can be scaled up or down based on demand.

The correct answer highlights that IaaS focuses specifically on the hardware aspects of cloud computing. With IaaS, users gain control over their computing resources without having to manage the physical infrastructure. This flexibility is beneficial for businesses that need to adapt their computing capacity quickly based on their operational needs.

The other options represent different layers and models of cloud services. Fully managed software applications refer to Software as a Service (SaaS), where the provider manages the entire application stack. Development tools and database management are aspects of Platform as a Service (PaaS), providing a platform for developers to build, deploy, and manage applications without dealing with the underlying infrastructure. Thus, the distinction between these service models clarifies why hardware resources provided as a service best describes IaaS.