The Word "Board" When Someone Uses It in Conjunction with the Production

The word "board" when someone uses it in conjunction with the production of a radio commercial refers to the:

A) group of people who are brought together during the preproduction phase of a commercial.
B) final recording of the ad before it is duplicated on dubs.
C) equipment for recording the sounds and channeling them to the appropriate recording devices.
D) delineated rehearsal format.
E) group of creatives that is responsible for editing the finished commercial.