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': 'Which of the following is true regarding local anesthesia? \nSelect and explain. \nA. They are basic salts of weak acids, B. Not effective in alkaline pH, C. Form salts with acids, D. They are acidic salts of weak bases', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]