What allows customers to run virtualized applications without relying on their own hardware?

The correct choice is Infrastructure as a Service (IaaS). IaaS provides customers with virtualized computing resources over the internet. This model allows users to run applications and store data on virtual machines managed by a third-party provider rather than relying on their own physical hardware. By utilizing IaaS, organizations can scale their resources as needed, avoid the costs and complexities associated with maintaining physical servers, and benefit from high availability and redundancy offered by the provider.

While Platform as a Service (PaaS) also supports application development without needing to manage the underlying infrastructure, it does not focus on providing virtualized hardware resources as a primary feature. Software as a Service (SaaS) offers software applications over the internet but does not provide any control over the underlying infrastructure or require hardware management. Community Cloud refers to a collaborative model where infrastructure is shared among several organizations with common concerns, but it does not inherently provide the same flexibility and scalability as IaaS does for running virtualized applications on demand.