This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'All of the following feature precipitate sickling of HBS except \nSelect and explain. \nA. Dehydration, B. Hypoxia, C. Infections, D. Increased PH', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Acidosis (↓ pH) precipitate sickling.', 'role': 'assistant'}]