question: Q:A 23-year-old man presents to the emergency room with right flank pain. On physical examination, there is no rebound tenderness, guarding, and rigidity. The pain is radiating to the groin region and is associated with nausea. Plain X-ray of the kidney, ureter, and bladder is normal. Urinalysis showed the presence of mild hematuria, an absence of pus cells, and the following crystals (refer to image). What is the most likely composition of these crystals?? 
  {'A': 'Calcium carbonate', 'B': 'Magnesium phosphate', 'C': 'Uric acid', 'D': 'Cysteine stones', 'E': 'Calcium oxalate'},