Labor Organization and the Haymarket Affair

In the period following the Civil War, labor movements became increasingly prominent as workers organized to fight for their rights and improve their working conditions. Various organizations emerged during this time, each with their own tactics and goals. One of the most notable events was the Haymarket Affair of 1886, which not only highlighted the struggles of labor unions but also influenced public perception of labor activism. Given this context, which of the following labor organizations was directly involved in advocating for an eight-hour workday and played a key role in the aftermath of the Haymarket Affair?