This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Concepts in Biochemistry, Subject name: Biochemistry
Preferred fuel for body in fasting state ? 
Select and explain. 
A. Carbohydrates, B. Fats, C. Proteins, D. Amino acids
B: Fats
Answer: B: Fats 
Explanation: Preferred fuel for body in fed state is mainly Carbohydrates i.e. Glucose. But in Fasting state, preferred fuel is mainly Fats & Adipose tissues are broken down to give energy. But some exceptions are there you should learn: See the table below. Fed Fasting Starvation Brain Glucose Glucose Ketone Bodies Hea Fatty Acids Fatty Acids Ketone Bodies Liver Glucose Fatty Acids Amino Acids Muscle Glucose Fatty Acids Fatty Acids and KB Adipose tissue Glucose Fatty Acids Fatty Acids RBC Glucose Glucose Glucose