This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'During exercise, blood flow to brain is \nSelect and explain. \nA. Decreased, B. Increased, C. Unaltered, D. Initially increased and then decreases', 'role': 'user'}, {'content': 'Answer: C \nExplanation: There is no change in the cerebral blood flow', 'role': 'assistant'}]