A Couple Has a Child with Down Syndrome When the Mother

Multiple Choice

A couple has a child with Down syndrome when the mother is 39 years old at the time of delivery. Which is the most probable cause?

A) The woman inherited this tendency from her parents.
B) One member of the couple carried a translocation.
C) One member of the couple underwent nondisjunction in somatic cell production.
D) One member of the couple underwent nondisjunction in gamete production.