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: Pathology
[{'content': "C D-99 is for - \nSelect and explain. \nA. Ewing's sarcoma, B. SLL, C. Dermatofibroma protruberans, D. Malignant histiocytic fibroma", 'role': 'user'}, {'content': "Answer: A \nExplanation: CD 99 is a marker associated with the diagnosis of Ewing's sarcoma.\nGranulosa cell tumour is also often found to be associated with CD 99.", 'role': 'assistant'}]