To Replace a Defective UPS, the Network Administrator Must Take

To replace a defective UPS, the network administrator must take the switch offline. The administrator wants to be able to perform maintenance UPS in the future without affecting the availability of the attached switch. Which of the following would BEST allow this to happen?

A) Add a redundant power supply to the switch
B) Implement stacking on the switches in the rack
C) Add a second UPS into the rack
D) Install a power converter for the switch