Why would Congress' passing of an act to make the first Monday in September of each year a legal holiday be an important development in the history of Labor Day? A. It recognized how the nation should plan celebrations held for the American Worker. B. It creates a national observance on the day originally selected by the central Labor Union in 1884. C. The act attributed the founding of the holiday to Matthew Maguire, a machinist. D. The act acknowledged the work of Peter J. McGuire, a cofounder of the American Federation of Labor.