Answer:c.Participants were affected by informational social influence.
Step-by-step explanation:
Informational Social influence occurs when an individual have their behaviour impacted to change by what is implied by others because they believe this is true then they conform to that idea.
A person who hears this information will want to be correct themselves hence the conformation to what they believe to be right.
Conserving energy will result to a reduced energy consumption, a person is very likely to believe this to be true and they would also want to be correct by changing their behaviour to conform to this and it also make sense that they may benefit from it.