A 70-Year-Old Man Presented to the Clinic with Recurrent Substernal

A 70-year-old man presented to the clinic with recurrent substernal chest pain. His pain is induced by exercise, relieved with rest. The patient is a known case of diabetes mellitus for 20 years. He is a heavy smoker. His blood pressure is 140/85 mm Hg and his pulse is 76/min. ECG showed old ischemic changes. Myocardial perfusion has been done and revealed ischemia at the anterior surface of the heart, involving the upper part of the interventricular septum. Which of the following coronary arteries is most likely affected in this patient?

A) Left anterior descending coronary artery
B) Left circumflex coronary artery
C) Left main coronary artery
D) Right coronary artery
E) Right marginal branch