Why was the use of labor unions by Polish workers effective in bringing democracy and capitalism to this Soviet bloc country? a.) The Soviet bloc countries had never encountered labor unions before, so they didn't understand how to oppose them. b.) Because of unions, communism failed to make workers labor purely for the benefit of state, without individual gain. c.) The Solidarity labor union gained enough political power to overthrow the communist "satellite" government in Poland. d.) Polish workers used labor unions to spread communist ideas to other countries throughout the communist bloc. Which letter?