The correct statement is: infrastructure-as-a-service (IaaS) is one type of cloud computing service where users pay only for the computing capacity they actually use.
IaaS provides users with a cloud-based platform for software development and deployment, allowing them to easily scale up or down their computing resources according to their needs. It typically includes virtualized computing resources such as servers, storage, and networking infrastructure that can be managed and accessed remotely. However, it does not provide software applications to users on demand or a service-oriented architecture for their systems, as those are features of other cloud computing services such as software-as-a-service (SaaS) and platform-as-a-service (PaaS), respectively.