The "Common Law of the Shop" Means That the Arbitrator

The "common law of the shop" means that the arbitrator:

A) disregards the past practice and intent of the parties, relying entirely on the labor
Agreement.
B) is concerned with how the decision affects the parties to the labor agreement, even
Though that decision might be different from another company having a different
Labor agreement.
C) relies on decisions obtained from other arbitrators and companies having different
Labor agreements to establish principles common to the overall industrial
Community.
D) all of these
E) none of these