Which of the Following Is a Feature of Heavy Metal

Which of the following is a feature of heavy metal intake and pregnancy?

A) Mercury, but not lead, can easily cross the placenta
B) The adverse effects of lead can be reduced by liberal intakes of calcium
C) Pregnant women are advised to limit consumption of shark and swordfish to no more than once per week
D) Pregnant women are advised to avoid shellfish around the critical period of brain development but may resume normal intake thereafter