What are the characteristics of the process of documenting the layers of an existing network? （）

• A、begins with gathering organizational input that may be inaccurate
• B、begins with gathering organizational input that does not need to be supplemented by a network audit
• C、requires a network audit to support some upgrade decisions
• D、requires a network audit to support any network restructuring
• E、provides reliable input for verifying network consistency
• F、does not provide reliable input for designing changes