Which statement is true?

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

Answer: (A)

Understanding how sheet-metal workers could move into energy-related roles in the 1970s highlights how building systems and energy efficiency began shaping career paths. The energy crisis and rising emphasis on conserving fuel and reducing operating costs created new opportunities in energy management. Sheet-metal workers already handle HVAC systems, including ductwork and system performance, so their hands-on knowledge naturally lent itself to roles focused on optimizing energy use in buildings, evaluating equipment, and implementing efficiency measures. That connection makes the statement about the 1970s true.

The other options don’t fit the historical pattern. World War I did not broadly decrease the need for skilled sheet-metal workers; wartime production often increased demand for skilled trades. In colonial America, apprenticeship arrangements varied, but masters were not universally required to provide wages to the apprentice—room, board, and training were commonly included, not guaranteed wages. In the 1980s, IAQ work is driven more by understanding ventilation, air quality, and building science rather than being based primarily on plumbing knowledge, so that statement isn’t an accurate characterization of how IAQ technicians typically enter the field.