Today, 80% of Babies with Down Syndrome Are Delivered to Women

Multiple Choice

Today, 80% of babies with Down syndrome are delivered to women under age 35. This is because

A) risk is negatively correlated with age.
B) Down syndrome is more often due to the father's age than the mother's age.
C) a vaccine has been developed for Down syndrome, and older women are more likely to get vaccinated.
D) amniocentesis is more likely to be performed on women over 35.