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
Drug of choice for acute (pneumococcal) lobar pneumonia is : 
Select and explain. 
A. Amoxicillin clavulanic acid combination, B. Ciprofloxacin, C. Co-trimoxazole, D. Crystalline penicillin (Pen. G)
D: Crystalline penicillin (Pen. G)
Answer: D: Crystalline penicillin (Pen. G) 
Explanation: None