C and d have to do with the upper classes and how they (mostly) utilized labor. Populists were more concerned with how to make things work for them (a bit cynical on my part).
The progressives (particularly women and labor leaders) were very concerned about working conditions and how to improve them.
B<<<< answer
East Germany was one combatant
A voilent protest, threats towards a school or a threat to a federal ran business such as a post office some banks police station etc.
Stalin helped Lenin escape from the authorities in order not to get captured
