Question

_______________ was a term given to journalists who exposed corruption and problems in society.

Answer 1

From what I can tell, the answer is Muckraker. These days, it's called "investigative" or "watchdog" journalism.

But yeah, a quick google search says that "the muckrakers were reform-minded journalists in the Progressive Era in the United States (1890's–1920's) who exposed established institutions and leaders as corrupt".