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': 'Single most impoant prognostic indicator of colorectal carcinoma is - \nSelect and explain. \nA. CEA titres, B. Degree of atypia, C. Size of tumor, D. Extent of tumour', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Extent of tumorThe single most impoant prognostic indicator of colorectal carcinoma is the extent of the tumor at the time of diagnosis, the so-called stage.", 'role': 'assistant'}]