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: Pharmacology
[{'content': 'Drug of choice for acute (pneumococcal) lobar pneumonia is : \nSelect and explain. \nA. Amoxicillin clavulanic acid combination, B. Ciprofloxacin, C. Co-trimoxazole, D. Crystalline penicillin (Pen. G)', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]