The correct answer is A) Jacob Riis.
Jacob Riis was a Progressive era muckraker who wrote one of the most famous books of the late 19th century. The book is called How the Other Half Lives. In this book, Riis uses descriptions and pictures to show the living conditions of immigrants in major cities (like New York). The goal of this was to expose the poor living conditions of these citizens in hopes that people would demand change regarding the conditions of tenements in major cities.
