Which statement is true?

• A. In the 1980s, sheet-metal workers' knowledge of plumbing systems allowed them to move into indoor-air quality (IAQ) technician positions.
• B. In colonial America, a master was required to provide food, lodging, clothing, and wages to the apprentice.
• C. In the 1970s, sheet-metal workers' knowledge of HVAC systems allowed them to move into energy-management positions.
• D. In 1884, the first metal airplane wing was stamped by William Dunn and Alfred Bowers.

Answer: (C)

Understanding how hands-on HVAC work translates into broader energy-efficiency roles helps explain why that statement is true. Sheet-metal workers install and tune HVAC systems—duct layout, airflow, balancing, and overall system performance. In the 1970s, energy shortages pushed building owners to cut energy use, creating a demand for professionals who could optimize how these systems operate. Those with solid HVAC knowledge were well positioned to move into energy-management roles, where they monitor performance, select efficient equipment, and implement control strategies to save energy.

The other options don’t fit the common career pathway as closely. The 1980s claim about moving into IAQ technician positions is related but reflects a broader field shift rather than a direct, typical progression from sheet-metal work. The colonial-era statement describes a general apprenticeship obligation not specific to the sheet-metal trade. The 1884 note about stamping a metal airplane wing is not aligned with established trade history.