The answer would be letter A. The contagion theory describes how propaganda affects collective behavior. It is an intense influence to people that may result to emotional outbursts and unreasonable actions. Contagion theory is one of theories of crowd behavior which was created by Gustave LeBon.
laws like these weren't really implemented in the north but were popular in the south because the south still had slavery until 1863, and because they wanted to deter slaves from running aware and also they wanted to keep control of what they had and of their property/slaves.
racism was rampant during the time against blacks because african americans didn't have rights at the time so they couldn't stand up for themselves or anything like that.
In Chapter 6 of "To Kill a Mocking Bird" by Harper Lee, Nathan Radley blames a black man for trespassing on his property on a summer night. He is quick to accuse the black man of doing such action, when in fact it was Jem Finch who committed the act of trespassing.
This situation shows how when a crime is committed in Maycomb county, the whole community will be quick to believe the worst of black people, but will not actually stop to asses the situation with caution and justice. In the book, the situation is turned into a joke, when Miss Stephanie declares that the shot "scared him pale". Nobody is taking the situation as a serious one because they all assume that what Nathan Radley is saying is true, because the accused is a black person.