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': 'Chacroid is caused by? \nSelect and explain. \nA. N. Gonnorrea, B. H. Ducrei, C. T. Pallidum, D. H. Influenza', 'role': 'user'}, {'content': 'Answer: B \nExplanation: See APPENDIX-47 for list of “STDs” CHANCROID (SOFT SORE) This venereal infection is caused by the Gram-negative bacillus Haemophilus ducreyi.\nOne to 5 days postinfection, a soft sloughy ulcer appears on the penis or vulva.\nThe treatment of choice is erythromycin (500 mg 6-hourly for 14 days).', 'role': 'assistant'}]