Which of the following is this an example of?

An organization wants to host a critical application on two redundant leased servers located on the ISP’s datacenter. Which of the following is this an example of?
A. PaaS
B. IaaS
C. Public cloud
D. SaaS

Correct Answer: B
Explanation/Reference:
Explanation:
Infrastructure as a service (IaaS) is an instant computing infrastructure, provisioned and managed over the Internet.
IaaS helps you avoid the expense and complexity of buying and managing your own physical servers and other datacenter 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. The cloud computing service provider manages the infrastructure, while you purchase, install, configure, and manage your own software—operating systems, middleware, and applications.

References: https://azure.microsoft.com/en-us/overview/what-is-iaas/