Fad Diets Often Produce Weight Loss, at Least Initially, for Which

Fad diets often produce weight loss, at least initially, for which of these reasons?

A) They dictate the correct distribution of energy among the macronutrients.
B) They prevent rapid spikes and declines in one's blood glucose level.
C) They don't require people to count kcalories, and are thus easier to stick to.
D) They are designed to limit energy intake to around 1200 kcal/day.