This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glycogen, Subject name: Biochemistry
During lack of food in diet , how many hours are needed for depletion of glycogen: 
Select and explain. 
A. 9, B. 18, C. 24, D. 48
B: 18
Answer: B: 18 
Explanation: Ans : option b -18 hrs (Best ans : 12-18 hrs) Glycogen reserves can be used for 12-18 hours.