This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
[{'content': 'In severe exercise, decrease in pH is due to: \nSelect and explain. \nA. Respiratory acidosis, B. Lactic acidosis, C. H+ retention, D. HCO3 excretion', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. (b) Lactic acidosis(Ref: Guyton, 13th ed/p.1085)Accumulation of lactic acid causes decrease in pH, muscle cramps and muscle fatigue,', 'role': 'assistant'}]