The correct answer is B.
OBJ-1.7: Infrastructure as a Service (IaaS) is the foundation of cloud computing. Rather than purchasing or leasing space in expensive datacenter, labor, real estate, and all of the utilities to maintain and deploy computer servers, cloud networks, and storage, cloud buyers rent space in a virtual data center from an IaaS provider. They have access to the virtual data center via the Internet. This type of cloud computing provides the “raw materials” for IT, and users usually only pay for the resources they consume, including (but not limited to) CPU cores, RAM, hard disk or storage space, and data transfer. Since this cloud provider is available to all companies to use, much like Microsoft Azure or Amazon Web Services, this is an example of a Public IaaS or Public Cloud.