What component of a VMware private cloud solution can be used to meet this requirement?

An administrator is considering a private cloud solution. The solution must allow for a 3 tiered
service model for development servers, application servers and business critical servers. What
component of a VMware private cloud solution can be used to meet this requirement?

A.
Organizations

B.
Service Catalogs

C.
Virtual Datacenters

D.
Allocation Models

Explanation:
http://www.vmware.com/files/pdf/services/VMware-On-Demand-ServicesWhitepaper.pdf(page 3, on-demand services)