A 27-year-old man presents to the emergency department with a 2-hour history of severe left-sided loin pain which woke him from sleep. The pain is constant but occasionally dulls. He has been feeling sick with the pain and vomited twice. On examination, the patient is writhing in agony and has mild tenderness in the left loin only. His temperature is 36.9°C. Urine dipstick shows 2+ of blood. What is the most likely diagnosis? A. Biliary colic B. Dissecting aortic aneurysm C. Pyelonephritis D. Renal cell carcinoma E. Renal colic