The answer is C. changing behavior.
Energy conservation involves reducing the amount of energy consumed by changing behavior. This can include simple actions like turning off lights when leaving a room or unplugging electronics when not in use, as well as larger changes like driving less or using energy-efficient appliances. While industry changes in energy production and investing in city policies to use renewable energy can also help reduce energy consumption, changing behavior is a critical component of energy conservation. Costly home renovations may also help reduce energy consumption, but they are not the primary focus of energy conservation.