Amuckraker was a reporter who wrote
about corruption and crime in industry and government.
fictional stories for newspapers and magazines.
about the importance of the first amendment.
editorials supporting industry leaders and big business practices.

A muckraker was a reporter who wrote about corruption and crime in industry and government. The correct option among all the options that are given in the question is the first option. He is the kind of reporter who actually concentrates on getting to the bottom of political and corporate corruption.

Primary sources are usually  more accurate and are written by someone who experienced it or witnessed it. secondary sources are those who heard of it after the fact that can lose details and or twist the event in a light that benefits them.