This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Physiology
[{'content': 'A 32 year old high altitude mountaineer is observed to have a hematocrit of 70 percent. Which of the following represents the most likely cause/explanation \nSelect and explain. \nA. Polycythemia with increased red cell mass, B. Relative Polycythemia due to dehydration, C. Polycythemia due to hemoconcentration, D. Polycythemia with high altitude pulmonary edema', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Polycythemia is usually seen in people living and high altitude and red blood cell mass is also increased Ref: guyton and hall textbook of medical physiology 12 edition page number:375,376,377', 'role': 'assistant'}]