In the Late Nineteenth Century, Why Was the Supreme Court

In the late nineteenth century, why was the Supreme Court willing to allow federal regulation of railroads and waterway transportation but less willing to allow regulation of factory and workplace safety?

A) The workplace is inherently local because the goods produced there have not yet passed into commerce and crossed state lines.
B) The Supreme Court ruled in McCulloch v. Maryland that the federal government had no power to regulate workplace safety, a precedent that was strictly followed until the New Deal.
C) During this period, the Supreme Court was staffed by Democratic appointees who sought to block federal workplace regulations.
D) During this period, most Supreme Court justices promised to support congressional regulation of transportation in their Senate confirmation hearings.