An intravenous pyelogram is performed on a patient to evaluate the function and structure of the her kidneys. Examination of the normal but radiographs reveals that the left kidney is normal but that there is a duplication of the ureter and renal pelvis on the right side. Further testing reveals that kidney function is normal. This variation is a result of abnormal development of which of the following structures?
(A)allantoic duct
(B)Metanephric blastema
(C)Mesonephric duct
(D)Mesonephric tubules
(E)Ureteric bud
Answer: (E)Ureteric bud