A Woman Who Is 6 Weeks Pregnant Tells the Nurse

A woman who is 6 weeks pregnant tells the nurse that she is worried that,even though she is taking folic acid supplements,the baby might have spina bifida because of a family history.The nurse's response should be based on what?

A) Prenatal detection is not possible yet.
B) There is no genetic basis for the defect.
C) Chromosome studies done on amniotic fluid can diagnose the defect prenatally.
D) Open neural tube defects (NTDs) result in elevated concentrations of a-fetoprotein in amniotic fluid.