What is the key objective of the plan phase？ Select exactly 1 answer（s） from the following：（）。
- Aidentify the activities involved in installing and configuring equipment at a customer’s site or sites
- BDescribe the day-to-day activities required to support， manage， and monitor a newly implemented system
- CAssess current network readiness， site readiness， and operational readiness in preparation for designing a solution proposal
- DGain an understanding of high-level business and technical requirement