Which nutrients may need special attention for pregnant women?

During pregnancy, certain nutrients play critical roles in supporting both maternal health and fetal development. The correct choice highlights the importance of folic acid, vitamin B, calcium, and iron.

Folic acid is crucial for preventing neural tube defects in the developing fetus, making it a critical nutrient during early pregnancy. Vitamin B (particularly B12 and B6) supports the development of the baby's brain and nervous system as well as helps maintain the mother's energy levels. Calcium is essential for building the baby's bones and teeth, while also helping maintain the mother's bone density. Iron is vital as it supports increased blood volume during pregnancy and is necessary for preventing anemia, which can occur when there is insufficient iron in the diet.

The other options mention nutrients that, while important for general health, do not have as direct a connection to pregnancy-specific needs as those listed in the correct answer. This places special emphasis on the mentioned nutrients which have well-documented roles in pregnancy nutrition.