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: Surgery
[{'content': 'Local anesthetic is not effective in an inflammed tissue because: \nSelect and explain. \nA. All impulses generated cannot be blocked, B. Myelin sheath is inflammed so it does not absorb the solution, C. pH is more acidic, so LA is ineffective, D. All of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]