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: Microbiology
[{'content': 'Lymphogranuloma venerum is caused by - \nSelect and explain. \nA. Chlamydia trachomatis, B. Calymmatobacter granulomatis, C. Haemophilus ducreyii, D. Treponema pallidum', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Chlamydia trachomatis", 'role': 'assistant'}]