B. It was the first time for many in working a factory
The Socialist League was formed from the socialists and the unions. The organization's main goal was to promote and fulfill the Labor Movement or the conditions of a socialist community. In socialism, there are no individuals who exist as "owners." Everyone is working together with the resulting wealth divided fairly among all the people.
In world war 2 industrial mobilization was more important. An example of this can be seen with the german reich. Germany at the beginning of the war had stockpiles of equipment to rely on and were a powerhouse that nearly won the war before the United States even entered however as they started getting bogged down their stockpiles dwindled and their industry could not keep up ultimately resulting in their downfall. Another reason for this is the fact it is easier to send allies equipment than it is to send them men.
