After Having a Son with a Severe Genetic Disease, a Couple

After having a son with a severe genetic disease, a couple working with doctors in the United States undergoes preimplantation genetic screening (PGS) to ensure that they have a girl. The couple is most likely trying to

A) balance the number of boys and girls in their family.
B) avoid having a baby with a sex-linked genetic defect.
C) have a healthier baby, because girls are statistically healthier.
D) minimize future expenses, because girls are less expensive to raise than boys.
E) help balance the U.S. population, which currently has more boys than girls.