How Are the Effects of Malnutrition on Human Fetal Development

How are the effects of malnutrition on human fetal development studied?

A) By using an experimental and control group design in which mothers are randomly given an inadequate or an adequate diet during pregnancy.
B) By examining birth records for babies born during periods of famine.
C) By using a survey technique to determine how hungry women are during pregnancy.
D) By cutting off the food supply to a random group of pregnant women for 3 days in the last trimester of pregnancy.