This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pathology
[{'content': 'The amount of blood lost in GIT to produce a single black stool is approximately \nSelect and explain. \nA. < 20 ml, B. 30-40 ml, C. 60-70 ml, D. 100-110 ml', 'role': 'user'}, {'content': 'Answer: C \nExplanation: approximately 60 ml of blood is required to produce a single black stool', 'role': 'assistant'}]