This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': 'Trachoma is one of the leading causes of blindness. Which of the following best typifies the disease? \nSelect and explain. \nA. It is caused by C. trachomatis, B. It is best treated with systemic cephalosporins and ophthalmic tetracycline, C. It affects 400 million people in the Pacific Rim, D. It is a form of chronic uveitis', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Trachoma is the most common cause worldwide of blindness. It is a chronic keratoconjunctivitis that affects about 400 million people and can be treated with sulfonamides and tetracycline. Relapse of trachoma is common.', 'role': 'assistant'}]