Question: A 56-year-old man comes to the emergency department because of a 4-day history of colicky right flank pain that radiates to the groin and hematuria. Ultrasound examination of the kidneys shows right-sided hydronephrosis and a dilated ureter. Which of the following is most likely to be found on urinalysis?
A: Glucose
B: Leukocyte casts
C: Oval fat bodies
D: Uric acid crystals
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option.