The Mother of a Six-Year-Old Brings Her Son to the Physician

The mother of a six-year-old brings her son to the physician because his teacher thinks he might have attention deficit/hyperactivity disorder (ADHD) . The nurse is interviewing the mother about the child's history. The nurse knows that which factors could be associated with ADHD?

A) Measles, mumps, and rubella vaccine
B) Advanced parental age
C) Prenatal exposure to smoke
D) Immune response