Final answer:
Before World War II, arbitration in labor disputes often relied on the arbitrator's diplomatic and persuasive abilities, as formal mechanisms like the National Labor Relations Board were not yet established.
c is correct
Step-by-step explanation:
Before World War II, the arbitrator's decision in labor disputes largely relied on c. Diplomatic and persuasive abilities to convince the parties that the decision should be accepted. While the National Labor Relations Act of 1935, also known as the Wagner Act, created the National Labor Relations Board (NLRB) to arbitrate disagreements between unions and employers, it wasn't until the mandate of this act and the establishment of the NLRB that formal mechanisms for enforcement were in place.
Prior to these institutions, arbitration was more heavily based on the skill of the arbitrator in convincing both sides to agree to a decision. A mention of the National Arbitration Act of 1902 is not relevant here, as it does not pertain to labor arbitration processes that were developed later on, particularly under the New Deal legislation.