John Is Studying the Case of a Bruce, 35-Year-Old Male

John is studying the case of a Bruce, 35-year-old male who lost his penis at circumcision. John interviews all the family members, reads medical records, and writes a book about the topic, focusing on how the surgery has affected Bruce's self-concept, gender identity, and sexual behavior. Most likely, John considers himself a . . .

A) humanist.
B) social psychologist.
C) sexologist.
D) forensic psychologist.