Dr. Haverford suggests to her clients that her mood problems stem from problems with the neurotransmitter serotonin. Dr. Haverford mentions nothing about social or behavioral factors that may be related to mood. According to the textbook, to understand her client's problems, Dr. Haverford seems to be using the ______ model
a. interdisciplinary
b. behaviorist
c. biopsychosocial
d. medical