Which statement is true?

• A. In 1876, the Globe Company improved the cornice brake.
• B. The Pittsburgh machine formed the Pittsburgh seam pocket lock through a series of handbrake bends.
• C. In the 1980s, sheet-metal workers' knowledge of plumbing systems allowed them to move into indoor-air quality (IAQ) technician positions.
• D. Tin plate was produced on a large scale in the United States in 1878.

Answer: (A)

This question tests knowledge of historical milestones in sheet metal tool development and how those advances affected fabrication of architectural metalwork. The statement about Globe Company improving the cornice brake in 1876 fits the era’s pattern of refining bending tools to produce precise, efficient forms for decorative building trims. The cornice brake is used to form long, consistent bends along the edge of metal to create cornices and other trim; an improvement from that period would likely involve sturdier construction, smoother operation, or adjustable dies, all of which would speed up production and improve accuracy for architectural work. The date 1876 sits squarely in the wave of late-19th-century tool enhancements that boosted shop productivity, making this the most defensible true statement.

The other items mix up timelines or attributions in ways that aren’t supported by typical historical records. A claim about a Pittsburgh machine forming a seam pocket lock purely through handbrake bends suggests a process that wouldn’t usually require a specialized machine for a standard pocket lock. The notion that sheet-metal workers moved into IAQ technician roles in the 1980s because of plumbing knowledge oversimplifies how those positions developed, which are more closely tied to HVAC and air-quality practices. The idea that tin plate was produced on a large scale in 1878 doesn’t align cleanly with the broader timeline of tin plate production and can-making history.