<prompt> A 67 year old man presented initially after a single episode of gross painless haematuria. An excretory urogram demonstrated a 1.5 mm round filing defect in the right lower renal infundibulum. The best study to obtain next is -Urinary cytologyCystoscopyUltrasonographyRetrograde pyelography  <response>: Ans. is c i.e., Ultra sonography 