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': 'All are good prognostic factors for neuroblastoma except - \nSelect and explain. \nA. Trk-A expression absent, B. Absence of 1 p loss, C. Absence of 17 p gain, D. Absence of 11 q loss', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Trk-A expression absent", 'role': 'assistant'}]