The Reformation; Luther sparked an avalanche of religious dissent towards the Roman Catholic Church, an institution which, at the time, held enormous power and influence over the lives of Europeans. Even the name of his new branch of Christianity, Protestantism, seems to bear that same rebellious spirit the compelled Luther to nail his theses to the church door.
Eugene Debs became a socialist in 1897 while c) serving time in jail. He was incarcerated after he was complicit with the Pullman Strike and he read various social works and became a more radicalized social worker than when he had gone into jail. This was when he became a founding member of three different American socialist parties.

Mostly because they didn't want to upset or worry the people they were sending the letter to, however they also didn't want to admit it to themselves.
Wealthy citizens. Progressive taxes are basically income tax. The less income you generate the less you have to pay with taxes. The more income you make, the more you have to pay in taxes.
Slavery looks to be the right answer