This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Medicine
[{'content': 'All are symptoms of acute mountain sickness except- \nSelect and explain. \nA. Headache, B. Dyspnoea, C. Tachycardia, D. Light headedness', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Whole body: fatigue, inability to exercise, loss of appetite, or low oxygen in the body Sleep: sleepiness or sleeping difficulty Gastrointestinal: nausea or vomiting Respiratory: rapid breathing or shoness of breath Also common: fast hea rate, headache, insufficient urine production, or respiratory distress syndrome Ref Harrison20th edition pg 2667', 'role': 'assistant'}]