Final answer:
The correct answer is (D) Increase the proportion of women who breastfeed their infants.
Step-by-step explanation:
In Healthy People 2020, one of the nutrition-related objectives for the nation for preconception is to increase the proportion of women who breastfeed their infants. However, breastfeeding is not specifically considered a preconception goal, but rather a postpartum goal. While breastfeeding provides numerous benefits for both the baby and the mother, it does not directly impact preconception health.
On the other hand, objectives (A), (B), and (C) are all related to preconception health. Increasing the proportion of women who take folic acid supplements before and during pregnancy helps prevent certain birth defects. Similarly, having a healthy weight before and during pregnancy is important for the overall health of the mother and the baby. Lastly, reducing the proportion of women who smoke during pregnancy helps minimize the risk of complications for both the mother and the baby.