In September 1884, leaders of five New York area locals called a conference to form which national organization?

The correct answer is the National Association of Pipe Trades. This organization was established in response to the need for a unified national presence for various trades involved in piping systems, which included plumbers, steam fitters, and gas fitters. The collaboration among the five New York area locals aimed to address common concerns, improve working conditions, and advocate for the interests of workers across these interconnected trades.

Understanding the broader context of labor movements during this period can also help clarify the significance of this organization’s formation. The labor unions of the late 19th century were pivotal in pushing for improved standards and fair practices within their respective industries, which is why establishing a national organization made sense for these tradespeople. The choice highlighting the National Association of Plumbers overlooks the inclusivity of the organization that represents multiple trades involved in piping, whereas options referencing steam fitters or gas fitters alone do not capture the full mission and intent of the conference that led to the foundation of the National Association of Pipe Trades.