Which Is the Best Explanation for Why Low-Carbohydrate Diets Work

Which is the best explanation for why low-carbohydrate diets work?

A) Low-carbohydrate foods are generally lower in calories than low-fat foods
B) Low carbohydrate diets reduce the secretion of insulin;insulin promotes the storage of fat
C) Low carbohydrate diets include lots of vegetables.
D) Low carbohydrate diets have a high glycemic index.