What defines Infrastructure as a Service (IaaS)?

Infrastructure as a Service (IaaS) is primarily defined by its provision of virtualized computing resources over the internet. This model allows businesses and individuals to rent virtualized hardware, such as servers, storage, and networking, instead of investing in physical infrastructure. By utilizing IaaS, users can dynamically scale their resources up or down according to their needs, leading to greater flexibility and cost efficiency.

IaaS typically includes services like virtual machines, load balancers, and firewalls, which all contribute to the management of computing infrastructure. This allows organizations to focus on their applications and services rather than the underlying hardware.

The other options do not encompass the full scope of IaaS. For instance, a service that only provides storage space falls more accurately under the category of cloud storage services, while a model for software development and a method for building applications without coding requirements align more closely with Platform as a Service (PaaS) and Low-Code/No-Code development solutions, respectively. Thus, the answer emphasizing virtualized computing resources captures the essence of IaaS effectively.