A 3-year-old girl's preferred make-believe game is playing house with her dolls. She loves to experiment with her mother's makeup and states that when she grows up, she will be a mommy. She is very offended when someone mistakes her for a boy. This scenario best demonstrates that which of the following is well established at this girl's age?
A. Theory of the mind
B. Sexual orientation
C. Gender identity
D. Gender neurosis
E. Gender dysphoria