This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidney, Subject name: Medicine
The most common cause of renal scaring in a 3 year old child is - 
Select and explain. 
A. Trauma, B. Tuberculosis, C. Vesicoureteral reflux induced pyelonephritis, D. Interstitial nephritis
C: Vesicoureteral reflux induced pyelonephritis
Answer: C: Vesicoureteral reflux induced pyelonephritis 
Explanation: Chronic pyelonephritis is characterized by renal inflammation and scarring induced by recurrent or persistent renal infection, vesicoureteral reflux, or other causes of urinary tract obstruction. VUR is a congenital condition that results from incompetence of the ureterovesical valve due to a sho intramural segment Ref Harrison20th edition pg 234