McClure's Magazine Pioneered a New Style of Journalism Featuring Writers

McClure's magazine pioneered a new style of journalism featuring writers like Ida Tarbell and Lincoln Steffens, who

A) scientifically analyzed social problems and proposed solutions.
B) provided voter information to reveal where candidates stood and whose money they accepted.
C) employed a gritty realism that portrayed life in the slums.
D) presented carefully-researched exposés of corporate and government abuses.