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: Skin
[{'content': 'Donovanosis/granuloma venerum is caused by \nSelect and explain. \nA. Calymatobacter granulomatis, B. T. peenue, C. Chlamydia Trachomatis, D. H. ducreyi', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. Calymatobacter granulomatis', 'role': 'assistant'}]