Answer:
c. Give them smiley or sad faces depending on how well they conserved energy.
Step-by-step explanation:
In the study Schultz did, he monitored the energy consumption of about 300 residents and he provided information about the energy consumption and some people also received an emoticon according to their consumption compared to the average energy use: a smiley or a frowning face.
The results showed that when people received this information, they changed their behavior. People with consumption over the average began controlling it and people with a consumption below the average became more relax. However, people that got smiley faces which means that their consumption was below average didn't start to waste energy. Because of this, to encourage people to use less electricity, you should give them smiley or sad faces depending on how well they conserved energy.