This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Rectum and anal canal, Subject name: Surgery
Most common location of solitary rectal ulcer is: 
Select and explain. 
A. Anterior wall, B. Right lateral wall, C. Posterior wall, D. Left lateral wall
A: Anterior wall
Answer: A: Anterior wall 
Explanation: Most common location of solitary rectal ulcer is: Anterior wall Solitary rectal ulcer syndrome (SRUS)- benign disease C/F- Rectal bleeding Copious mucus discharge Prolonged excessive straining, feeling of incomplete defecation, constipation Perineal and abdominal pain Histopathological features- obliteration of the lamina propria by fibrosis and smooth muscle fibers extending from a thickened muscularis mucosa to the lumen. COLONOSCOPY WITH BIOPSY is the investigation of choice