The expenditure models are either CapEx or OpEx (Capital or Operational). CapEx is what you pay upfront, on prem, for servers, racks, cooling, security, the Datacenter itself. OpEx is what you pay to keep your infrastructure operational, like IT staff. In this case, when you move to the Cloud, what you identify in this case is the OpEx or Operational model. This is because you actually don't have CapEx on the Cloud (or at least you look to minimize CapEx) as you pay for the resources you use and not for the underlying hardware, security, cooling, etc that you will pay for in an On-Prem solution. That is why the right answer is (A) Operational. Elastic and Scalable are not expenditure models.