The Nurse Is Working with an Infant Who Has Trisomy

The nurse is working with an infant who has trisomy 21 and an atrioventricular septal defect (AVC) . The father asks the nurse about the percentage of children with Down syndrome who have atrioventricular septal defects. Which of the following is the nurse's best explanation?

A) "Atrioventricular septal defects are very rare in children with Down syndrome because they usually occur without any other congenital anomalies."
B) "About 50% of children with Down syndrome have some congenital heart defect, and many of these are associated with some degree of atrioventricular septal defect."
C) "Less than 3% of children with Down syndrome will have an associated heart defect."
D) "Approximately 90% of the children who are born with Down syndrome have atrioventricular septal defects."