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: Medicine
This clinical sign is seen in <img src=" /> 
Select and explain. 
A. Carcinoma colon, B. Ulcerative colitis, C. Crohn's disease, D. Tuberculosis
C: Crohn's disease
Answer: C: Crohn's disease 
Explanation: This is a contrast study showing string sign of KantorIn Crohn&;s disease, edema, bowel wall thickening, and fibrosis of the bowel wall within the mass account for the radiographic "string sign" of a narrowed intestinal lumen.Ref: Harrison 19e pg: 1953