This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: S.T.D., Subject name: Skin
[{'content': 'A sexually active male comes with multiple painful ulcers, the smear is enclosed? What is the most likely diagnosis? \nSelect and explain. \nA. Chancre, B. Chancroid, C. Herpes, D. Aphthosis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B. ChancroidImage shows pleomorphic gram negative coccobacilli (H. ducreyi) arranged in a parallel chains of two\'s or four described as "School of fish"', 'role': 'assistant'}]