The correct answer is D)His socialist politics.
Upton Sinclair's book The Jungle was written in order to expose the horrible working conditions faced by American citizens due to the capitalist system in place. Part of this book was originally written for a newspaper called "Appeal to Reason", which at this time was a socialist newspaper. Ultimately, Sinclair was appealing to the working class of America to try to persuade them that the capitalist system being used by the US was not working.
