What is the first step that an engineer should take to troubleshoot this issue?

The microphone on a Cisco TelePresence System 3000 is switching incorrectly to a camera that does not have an active speaker.

What is the first step that an engineer should take to troubleshoot this issue?
A . Check whether the microphone is properly plugged in.
B . Run the microphone calibration procedure.
C . Plug all microphones into the primary codec.
D . Check whether the cable from the microphone is plugged into the correct receptor on the codec.

Answer: B