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': 'All of the following statements regarding Chlamydia are true, except: \nSelect and explain. \nA. Gram positive, B. Trachoma, C. Causes Psittacosis, D. Causes Lymphogranuloma venerum', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Chlamydia are gram negative, non motile, obligate intracellular parasites which multiply in the cytoplasm of host cells. Chlamydia trachomatis serotypes A, B and C cause trachoma, L1-3 serotypes cause lymphoganuloma venerum, D-K serotypes cause genital tract infection and conjunctivitis. Pscittacosis is caused by Chlamydia psittaci.', 'role': 'assistant'}]