Low-fat, low-cholesterol, and dairy-free diets are all diets that are necessary for
a. religious reasons
b. moral reasons
c. ethical reasons
d. health reasons

It's D, because its related  to your health and they are existing health diets

a mother eats twice as much to support her growing fetus

limiting sugar intake in a mother with gestational diabetes, switching from diving to swimming.   depending on whether the patient is normal weight, over weight or gain will differ depending on that.