【单选题】Since the lineage of investigative journalism is most directly traceable to the progressive era of the early 1900's, it is not surprising that the President of the United States at the time was among ...
A.
John Bunyan's Pilgrim's Progress and one of its characters 'Muckrakers'
B.
its function of cleaning the dirt off the floor in public places
C.
its relentless exposures of political and social evils
D.
its indispensable status to the well-being of society