During the late nineteenth century the U.S. economy underwent a spectacular increase in industrial growth. Abundant resources, an expanding labor force, government policy, and skilled entrepreneurs facilitated this shift to the large-scale production of manufactured goods. For many U.S. citizens industrialization resulted in an unprecedented prosperity but others did not benefit as greatly from the process. The expansion of manufacturing created a need for large numbers of factory workers. Although the average standard of living for workers increased steadily during the last decades of the nineteenth century, many workers struggled to make ends meet. At the turn of the century it took an annual income of at least $600 to live comfortably but the average worker made between $400 and $500 per year.
<span>"Racism was deeply felt throughout the nation, and the civil rights gains of the Reconstruction period were rolled back by Jim Crow laws."</span>
The "Red Shirts" are mostly associated with the period that followed after the Reconstruction era of the United States of America. Although they were present from the year 1875 but they became most active after the Reconstruction era. So it can be said that during the late 19th century the "Red Shirts" were most active.
Hiring a substitute so A is the answer.
The highest rank would be Genius