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': 'Rx of latent syphilis  a) Penicillin  b) Erythromycin  c) Tetracycline  d) Ciprofloxacin \nSelect and explain. \nA. ac, B. ab, C. bc, D. bd', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]