This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: G.I.T., Subject name: Pathology
All are seen in Crohn's disease EXCEPT 
Select and explain. 
A. Poor perianal hygiene, B. Stricture formation, C. Crypt abscess, D. Rectum is commonly involved
D: Rectum is commonly involved
Answer: D: Rectum is commonly involved 
Explanation: Ref: Robbins Pathology, 9th ed. pg. 798-99* Crohn's disease can lead to formation of perianal fistula which leads to poor perianal hygiene.* The stricture formation seen in Crohn's disease occurs due to transmural inflammation.* Most common part of GIT involved is ileum in Crohn's disease and rectum is spared.* Fecal lactoferrin is a highly sensitive and specific marker for detecting intestinal inflammation.* Fecal calprotectin levels correlate well with histological inflammation and predict relapses and detect pouchitis.