The correct answer is: It appeals to the audience's innate desire to follow the crowd or fit in it.
A bandwagon appeal is a type of fallacy characterized by asuming that the opinion fo the majority is always valid. "If everyone thinks it is correct then it must be correct." It can only prove that something is popular but not that it is correct.
Psychology has proven that humans naturally follow crowd behaviour in a very automatic way. So by using this types of arguments, it is very easy to convince people of some things that are not always correct.
In this case they show us that 90 percent of people preferred Glisten toothpaste and they want us to relate it to a correct decision, if they preferred it, it must be good. The truth is that we can't know that information unless we compare different types of toothpaste and select the best one for us.