A 25yearold pregnant woman comes for genetic counseling and amniocentesis because her father had Becker muscular dystrophy (BMD). Ultrasonography shows a male fetus. Her father's mutation is known. Test results show that neither the woman nor her fetus carries the BMD mutation. The woman is not aware that her father is not her biological father. Which of the following is the BEST course of action for the genetic counselor?

A. Consult with the ethics review board regarding the best course of action.
B. Tell the woman that the results indicated that her fetus is not affected.
C. Arrange a session for the woman and her mother to discuss nonpaternity.
D. Contact the woman's obstetrician with the test results, and let him inform her.