People are most likely to apply the fundamental attribution error to

Celebrity

Explanation:

Fundamental attribution error occurs when the personal characteristics of a certain individual make us possessed a biased view of a certain type of information

For example, Lebron is arguably the most famous basketball star and a huge celebrity in the eyes of many people.

Let's say that there is a video uploaded of lebron eating a specific brand of cereal before he went out to practice. Just by seeing that scene, large number of people will make a fundamental attribution error and believing that that specific brand of cereal provide the best nutritional value for athlete levels since someone like lebron consume it before his practice.