Answer:
C. her belief in an imaginary audience.
Step-by-step explanation:
Imaginary audience: In psychology, the term "imaginary audience" is determined as a condition in which a person believes, thinks, and imagines that many different individuals are watching or listening to her or him madly or exuberantly.
According to psychologists, an imaginary conditioned is believed to be seen mostly in "young adolescence yet any person can develop this condition irrespective of their age by fantasizing or imagining the audience.
In the question above, the given statement signifies that Marsha is demonstrating an imaginary audience.