a. It's when a person thinks so much about themselves and starts thinking about how other people are thinking the same thing as them. (Cognitive development)
b. When Vanessa gets an email about her hair looking bad. She starts thinking that her hair looks bad and everyone else in the school is thinking bad about her hair looks. She decides to chop it off.
c. This is an example of imaginary audience because of how Vanessa is more focused and concerned about how others are thinking like her.