How does chemistry affect the food you eat

When stress, toxins or lack of essential nutrients weaken digestion, harder to digest foods like grains and cow dairy, meat and processed foods contribute to maldigestion, dysbiosis and impaired digestive competence.

Most likely a is the answer - because  you generate   38 atp's but also consume an atp.   each atp gives approx. less than 4 kcal so probably a is the closest answer.