A

The Knights of Labor was a poorly organized labor union tasked with promoting the rights of the working population in the 19th century.

Explanation:

The Knights of Labor is the term referring to the history of the labor movement in the United States and other English-speaking countries. The Knights of Labor was among the first and the most well-known national labor organizations in the USA. It came into existence at the very end of the 1860s as a small secret society of dressmakers living and working in Philadelphia.

The next few decades were marked by the organization’s gradual growth and successful efforts to attract new members and demand just attitudes to the working class. In particular, by the middle of the 1880s, about 700,000 people were its members and took part in the Knights’ activities. The Knights of Labor united a number of ambitious workers, some of which contributed to the development of other bodies, including the American Federation of Labor (AFL).

It is just to call it the unique and truly revolutionary society due to multiple facts, including the Knights of Labor’s membership requirements that were quite progressive for the time. People allowed to join the organization included workers in diverse industries, those fulfilling low-skilled and unskilled jobs, female workers, and even racial and ethnic minority workforce.

The group used different forms of protest to pursue its basic goals, such as changing the legal status of child labor, regulating working day length, and reducing unfair pay gaps.

Despite its noble goals appealing to the working class, the organization could not maintain its high popularity. It started losing members after 1886 as a result of the emergence of other, more flexible organizations, such as the AFL, the weaknesses of its organizational structure, and the alleged participation in the so-called Haymarket Affair.