This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Atherosclerosis impedes coronary blood flow by which of the following mechanisms? 
Select and explain. 
A. Plaques obstruct the vein, B. Plaques obstruct the artery, C. Blood clots form outside the vessel wall, D. Hardened vessels dilate to allow blood to flow through
B: Plaques obstruct the artery
Answer: B: Plaques obstruct the artery 
Explanation: Option A: Arteries, not veins, supply the coronary arteries with oxygen and other nutrients.
Option C: Atherosclerosis is a direct result of plaque formation in the artery.
Option D: Hardened vessels can’t dilate properly and, therefore, constrict blood flow.