A couple seeks counseling because their first child was born with a ventricular septal defect. There is no family history of any congenital heart disease, and the parents have normal cardiac examinations. They should be counseled that the risk that a subsequent child will have a similar or other cardiac defect is closest to
A. less than 1%.
B. 3-5%.
C. 8-10%.
D. 2-5%.