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
Maximum reservoir of blood 
Select and explain. 
A. Large vein, B. Aoa, C. Hea, D. Capillaries
A: Large vein
Answer: A: Large vein 
Explanation: At rest, at least 50% of the circulating blood volume is in the systemic veins, 12% is in the hea cavities, and 18% is in the low-pressure pulmonary circulation. Only 2% is in the aoa, 8% in the aeries, 1% in the aerioles, and 5% in the capillaries Ref: Ganong's Review of Medical Physiology Twenty-Third Edition Page No:543