This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'A child is born with a single functional copy of a TSG. At the age of 5, the remaining normal allele is lost through mutation. As a result, the ability to control transition from G1 to S phase of cell cycle is lost. Which neoplasm is mot likely to arise in this child? \nSelect and explain. \nA. Retinoblastoma, B. Breast carcinoma, C. Adenocarcinoma colon, D. Cerebral astrocytoma', 'role': 'user'}, {'content': 'Answer: A \nExplanation: .', 'role': 'assistant'}]