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
Fahraeus Lindquist effect is: 
Select and explain. 
A. 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
A: Increase in viscosity in vessels less than 0.5-1 mm in diameter
Answer: A: Increase in viscosity in vessels less than 0.5-1 mm in diameter 
Explanation: Ans. A. Increase in viscosity in vessels less than 0.5-1 mm in diameter