Which of these is the best definition of the Cisco Lifecycle Services approach？ Select exactly 1 answer（s） from the following：（）。

A. It defines the minimum set of services required to successfully deploy and operate a set of Cisco technologies
B. It determines how best to price Cisco products
C. It provides partners with a useful way to leverage Cisco resources
D. It consists of these phases： plan， deploy， support， and troubleshoot