A low-carbohydrate diet is most likely the cause of Suzanne's low energy during workouts, as these diets often restrict carbs, which are a primary source of energy for physical activity. Additionally, while low-fat diets are typically aimed at reducing cholesterol, it's possible for someone on a low-carbohydrate diet to experience higher cholesterol levels due to increased intake of fats and proteins. Therefore, the answer is:
A. low-carbohydrate.