This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection, Subject name: Medicine
[{'content': 'The drug of choice for the treatment of chlamydial infection is- \nSelect and explain. \nA. Ampicillin, B. Third generation cephalosporins, C. Metronidazole, D. Doxycycline', 'role': 'user'}, {'content': "Answer: D \nExplanation: A 7-day course of tetracycline (500 mg four times daily), doxycycline (100 mg twice daily), erythromycin (500 mg four times daily), or a fluoroquinolone (ofloxacin, 300 mg twice daily; or levofloxacin, 500 mg/d) can be used for treatment of uncomplicated chlamydial infections. A single 1-g oral dose of azithromycin is as effective as a 7-day course of doxycycline for the treatment of uncomplicated genital C. trachomatis infections in adults. (Harrison's Principles of internal medicine, 20th edition, page 1426)", 'role': 'assistant'}]