You are answering a USMLE-style medical question. Question: A 64-year-old man with coronary artery disease and hypertension comes to the physician for a follow-up examination. His blood pressure ranged from 160/100 mm Hg to 150/94 mm Hg on his previous 3 visits over the past 4 months. Current medications include aspirin, atorvastatin, hydrochlorothiazide, and metoprolol. Three weeks ago, he was also started on amlodipine. His blood pressure today is 158/98 mm Hg. Physical examination shows no other abnormalities. Renal duplex ultrasonography shows 90% occlusion of the right renal artery. Decreased renal blood flow is most likely to cause which of the following? Options: A) Hyperplasia of juxtaglomerular cells B) Dilation of efferent arteriole C) Decreased prostaglandin synthesis by macula densa D) Decreased reabsorption of bicarbonate at proximal tubule Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.