Which of these phases involves ensuring that a new solution has been integrated without disrupting the existing network？ Select exactly 1 answer（s） from the following：（）。

A.improving the network management system and the performance and functionality of infrastructure operations
B.providing a step-by-step plan that details the installation and service-commission tasks required in order to create a controlled-implementation environment that emulates a customer network
C.developing and implementing a training plan using classes， workshops， or c-learning courses
D.compiling a training manual for use in ongoing operations
E.reducing the risk of downtime due to facilities-related problems

A.providing a partner with information regarding customer acceptance of a new Solution
B.providing information regarding current network infrastructure readiness
C.using stakeholder interviews to identify stakeholders and decision-makers， high-level solution requirements， timelines， and the scope of an opportunity
D.adjusting a solution to account for a customers physical site characteristics

A.Technology Strategy Development
B.High-Level Design Development
C.Business Case Development
D.Proof of Concept