This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Medicine
Complete occlusion of coronary artery is denoted by which score in TIMI by angiography? 
Select and explain. 
A. 0, B. 1, C. 2, D. 3
A: 0
Answer: A: 0 
Explanation: Ans. A. 0Coronary AngiographyWhen assessed angiographically, flow in the culprit coronary artery is described by a simple qualitative scale called the thrombolysis in myocardial infarction (TIMI) grading system:a. Grade 0 indicates complete occlusion of the infarct-related arteryb. Grade 1 indicates some penetration of the contrast material beyond the point of obstruction but without perfusion of the distal coronary bedc. Grade 2 indicates perfusion of the entire infarct vessel into the distal bed but with flow that is delayed compared with that of a normal arteryd. Grade 3 indicates full perfusion of the infarct vessel with normal flow.