In the process of equipment installation, which of the following statements are wrong?

In the process of equipment installation, which of the following statements are wrong?
A . Wear anti-static gloves or an anti-static wrist strap before touching the device, holding the plug-in board, single board, ICA chip, etc.
B. Inside the cabinet, the binding interval of the cable buckle/fiber binding band of the optical fiber shall not exceed 250mm, and the binding interval of the cable buckle of the user cable shall not exceed 200mm
C. In order to dissipate heat, the empty slots on the network element do not need to be inserted with filler panels
D. When plugging and unplugging a single board with connecting cables or pigtails on the panel, unplug the connecting cables or pigtails first, and then plug in and out

Answer: C