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': "Marjolin ulcer \nSelect and explain. \nA. Ca in marjolin's is squamous cell ca, B. Chronic venous insufficiency, C. Basal cell carcinoma, D. arise from base of the ulcer", 'role': 'user'}, {'content': 'Answer: A \nExplanation: .marjolin&;s ulcer is the name given to a malignancy ( usually a squamous cell carcinoma ) which arise in any long standing wound or a scar mostly scar of an old burn it grows slowly as it is avascular it is painless', 'role': 'assistant'}]