Which statement is true?

• A. World War I decreased the need for skilled workers in the sheet-metal trade.
• B. In colonial America, a master was required to provide food, lodging, clothing, and wages to the apprentice.
• C. In the 1980s, sheet-metal workers' knowledge of plumbing systems allowed them to move into indoor-air quality (IAQ) technician positions.
• D. In the 1970s, sheet-metal workers' knowledge of HVAC systems allowed them to move into energy-management positions.

Answer: (D)

Understanding how HVAC knowledge translates into broader building-energy roles helps explain why this statement is true. In the 1970s, as energy costs rose and efficiency programs gained importance, the field of energy management expanded. Sheet-metal workers are trained in the details of HVAC systems—duct design and layout, airflow, sealing, and how equipment and controls affect energy use. That hands-on expertise makes them well suited to roles that assess a building’s energy performance, plan retrofits to cut consumption, and supervise energy-management programs. So moving into energy-management positions fits the career evolution for sheet-metal tradespeople during that era.

The other statements don’t fit the historical context as cleanly. For example, during World War I the demand for skilled workers in the trades actually increased due to wartime production, not decreased. In colonial America, apprenticeship bonds typically covered training and basic room-and-board, but wages were not automatically guaranteed in the way the statement suggests. And while IAQ work in the 1980s drew on knowledge of ventilation and building systems, plumbing expertise isn’t the most direct path into IAQ technician roles; those positions tended to align more with HVAC and environmental controls than with plumbing alone.