Answer: The American Federation of Labor
Explanation:
The American Federation of Labor (AFL) was formed in December 1886 by craft unions who were unhappy with a national labor union known as the Knights of Labor.
The AFL became the largest labor union from then and for much of the early 20th century. With the numbers and influence they wielded, they were able to win wage increases for their members as well as shorter work weeks in their most prominent years which were between 1890 and 1915.