How did reformers expose the living conditions to the public?

To expose and reform corruption in politics.

Explanation:

Since 1892, Steffens worked for the New York Evening Post. He later turned into the distributer of McClure's Magazine, from where he co-built up an analytical style called muckraking, revealing corruption in the American culture, with a special accentuation in New York.  

After 1910, Steffens'reporting on corruption  bit by bit reduced. Rather, his attention was on the Mexican Revolution. He turned into a heartfelt supporter of the alleged rebels and concentrated increasingly more on the insurgency as the best way to escape capitalism.

people had jobs and began to work. that’s why the commercial revolution was great.

i believe out of the choices it is a.