The National Park Service wants to reduce the littering in its parks by putting up signs that influence visitors not to litter. Based on the influence principles covered in class materials, which of the following signs would be the most effective way to persuade visitors not to litter?
"85% of our park guests don't litter."
“Please don't litter."
"85% of people enjoy spending time in the park."
"Please help the environment by not littering."
"85% of people in the country don't litter."