Sophia and Her Brother James Are Both Taking a Psychology

Sophia and her brother James are both taking a psychology class together, and are studying for an examination. "I just can't remember where the body produces the majority of its serotonin," complains James. Sophia helps him by saying, "just remember that it is produced in the enteric nervous system, and you should have no problem knowing that the ________ is the body part you're looking for."

A) gastrointestinal system
B) basal ganglia
C) pons