Before World War II$,$ the arbitrator's decision largely relied on:

a$.$

The National Labor Relations Board for enforcement.

b$.$

Criminal convictions under the National Arbitration Act of $1902.$

c$.$

Public opinion.

d$.$

The National Labor Relations Board for enforcement and criminal convictions under the National Arbitration Act of $1902.$

e$.$

Diplomatic and persuasive abilities to convince the parties that the decision should be accepted.