This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
What is column of beini in kidney ? 
Select and explain. 
A. Renal tumour, B. Tongue like papillary projection, C. Calculus, D. None
B: Tongue like papillary projection
Answer: B: Tongue like papillary projection 
Explanation: The renal column (or Bein column , or column of Bein ) is a medullary extension of the renal coex in between the renal pyramids. The hyperophy of these columns is a benign condition sometimes mistaken for a renal tumor .