This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Physiology
[{'content': 'The velocity of blood is maximum in the \nSelect and explain. \nA. Large veins, B. Small veins, C. Venules, D. Capillaries', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Large veins have so little resistance to blood flow when they are distended that the resistance then is almost zero and is of almost no impoance. Ref: Guyton and Hall textbook of medical physiology 13th edition. Page: 184', 'role': 'assistant'}]