Answer: Carbohydrates
Explanation: Carbohydrates are the main source of fuel for athletes, especially those participating in endurance sports. It is more beneficial to eat a low glycemic carbohydrate (oatmeal, yams, brown rice, 100% whole grains) meal 3–4 hours before exercising or athletic competition.
The nonfat part of the body termed as lean body mass. Technically, it’s the amount of weight on the body which is considered as nonfat. Lean body mass is an important consideration as its weight must be relatively constant. So, if you’re aiming a body shape or weight especially if you’re an athlete, body builder, etc. your lean body mass should not change rather you burn or reduce your body fat percentage.
Smoking...
Smoke can cause cancer, gum problems, and other health problems.
So that's definitely not a healthy lifestyle.
The answer is A if I'm not mistaken