This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Muscle, Subject name: Physiology
[{'content': 'A person who is running, the main source of energy he will be using in 1st min is: \nSelect and explain. \nA. Glucose, B. Glycogen, C. Fat, D. Phosphagen', 'role': 'user'}, {'content': 'Answer: B \nExplanation: "The major sources of energy in the 100-m sprint are creatine phosphate (first 4-5 sec) and then anaerobic glycolysis using muscle glycogen as the source of glucose."', 'role': 'assistant'}]