This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: M.I. & Angina, Subject name: Medicine
ECG of a patient had ST segment elevation in VI-V6, lead I and aVL. Which of the following branches is involved? 
Select and explain. 
A. Left main coronary artery, B. Left anterior descending, C. Diagonal 1 branch of LAD, D. Septal branch of LAD
A: Left main coronary artery
Answer: A: Left main coronary artery 
Explanation: Ans. (a) Left main coronary artery.