This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Respiratory system, Subject name: Anatomy
Treatment of Chlamydia pneumonia is 
Select and explain. 
A. Erythromycin, B. Ceftriaxone, C. Penicillin, D. Sulphonamide
A: Erythromycin
Answer: A: Erythromycin 
Explanation: Although few controlled trials of treatment have been repoed, C. pneumoniae is inhibited in vitro by erythromycin, tetracycline, azithromycin, clarithromycin, gatifloxacin, and gemifloxacin. Recommended therapy consists of 2 g/d of either tetracycline or erythromycin for 10-14 days.. Ref Harrison 19th edition pg 1147