The correct answer is B.
OBJ-4.1: Infrastructure as a service (IaaS) is an instant computing infrastructure, provisioned, and managed over the internet. Infrastructure as a Service (IaaS) is a cloud computing service that enables a consumer to outsource computing equipment purchases and running their own data center. IaaS quickly scales up and down with demand, letting you pay only for what you use. It helps you avoid the expense and complexity of buying and managing your physical servers and other data center infrastructure. Each resource is offered as a separate service component, and you only need to rent a particular one for as long as you need it. A cloud computing service provider manages the infrastructure while you purchase, install, configure, and manage your software. Platform as a Service (PaaS) is a cloud computing service that enables consumers to rent fully configured systems that are set up for specific purposes. Software as a Service (SaaS) is a cloud computing service that enables a service provider to make applications available over the Internet to end-users. This can be a calendar, scheduling, invoicing, word processor, database, or other programs. For example, Google Docs and Office 365 are both word processing SaaS solutions. Desktop as a Service (DaaS) provides a full virtualized desktop environment from within a cloud-based service. This is also known as VDI (Virtualized Desktop Infrastructure) and is coming in large enterprise businesses focused on increasing their security and minimizing their operational expenses.