This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General surgery, Subject name: Surgery
[{'content': 'Most common type of melanoma \nSelect and explain. \nA. Nodular melanoma, B. Superficial spreading melanoma, C. Lentigo maligna melanoma, D. Acral lentigious melanoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Superficial spreading melanoma (SSM) This is the most common presentation (70%), usually arising in a pre-existent naevus after several years of slow change, followed by rapid growth in the preceding months before presentation.Ref: Bailey and Love, 27e, page: 609', 'role': 'assistant'}]