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: Gynaecology & Obstetrics
[{'content': 'Which of the following statements about Chlamydia trachomatis is true: \nSelect and explain. \nA. May be isolated on aificial media by culture of purulent endocervical discharge, B. Most genital chlamydial infections are symptomatic, C. Use of OCP is associated with increased risk of asymptomatic chlamydial infection, D. Penicillin is the drug of choice for treatment', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Patients on treatment with oral contraceptives have a increased risk of asymptomatic chlamydial infections. Ref: Clinical Obstetrics and Gynaecology by Brian A. Magowan, Philip Owen, James Drife, Pages 126-128.', 'role': 'assistant'}]