A 72-year-old man with a history of hypertension and hyperlipidemia presents with acute chest pain and diaphoresis. His ECG demonstrates ST-segment elevations in leads II, III, and aVF, consistent with an inferior wall myocardial infarction. Emergent coronary angiography shows that the vessel running in the posterior interventricular sulcus arises from the left atrioventricular (coronary) groove. Occlusion of which coronary artery is most likely responsible for this infarction in this patient?