The correct installation method is the precondition for ensuring the normal operation of the ONU. Which of the following is the wrong installation method?

The correct installation method is the precondition for ensuring the normal operation of the ONU. Which of the following is the wrong installation method?
A . Ground wire connected to ground bar
B . The casing of the customer line should be protected with a sleeve
C . Fiber optic dust caps should be installed when the optical fiber is not in use
D . Signal lines and power lines should be centralized

Answer: D