This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Heart, Circulation, and Blood, Subject name: Physiology
[{'content': 'Fahraeus Lindquist effect is: \nSelect and explain. \nA. Increase in viscosity in vessels less than 0.5-1 mm in diameter, B. Decrease in viscosity in vessels less than 0.5-1 mm in diameter, C. Increase in viscosity in vessels more than 0.5-1 mm in diameter, D. Decrease in viscosity in vessels more than 0.5-1 mm in diameter', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. A. Increase in viscosity in vessels less than 0.5-1 mm in diameter', 'role': 'assistant'}]