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: Dental
[{'content': 'Painful ulcers over genitalia are caused by – \nSelect and explain. \nA. Primary syphilis, B. Granuloma inguinale, C. Chancroid, D. LGV', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]