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': 'The following acute respiratory response to ascent to high altitude, there is normalization of blood pH. The mechanism is \nSelect and explain. \nA. Increased erythropoesis leads to increased buffering by hemoglobin, B. Increased excretion of HCO3 - by the kidneys, C. Increased levels of 2, 3--DPG, D. Retention of bicarbonate by the kidneys', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The lung response to acute altitude exposure is mainly hyperventilation which, together with elevated hea rate, aims at achieving an adequate supply of oxygen to the tissues. At rest, ventilation increases by firstly increasing the tidal volume, at least up to 3500 m. Ref: guyton and hall textbook of medical physiology 12 edition page number:365,376,377', 'role': 'assistant'}]