Karl Marx argued that what played a key role in keeping the working poor from engaging in revolutionary social change that he believed was necessary to improve their situation?

Religion

Explanation:

Religion has always been and would always be a major decider in the decision of people in the society, especially society which is occupied by people who are not really high income earners. Society with high income earners tend to easily shrug off the religion mentality and go for what they want but that which is mostly occupied of low income earners place all their hopes and their next move in decision making tied to what their religion would say concerning what's the topic and what decision they should be making.

the best and most correct answer among the choices provided by the question is the second choice "less supportive to the war of 1812"

the war of 1812 was a military conflict that lasted from june 1812 to february 1815, fought between the united states of america and the united kingdom, its north american colonies, and its native american allies.

i hope my answer has come to your . god bless and have a nice day ahead!