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
A 22-year-old man with inflammatory bowel disease is noted to have a "string sign" in the ileal area on barium enema. In which of the following conditions is this sign most often seen? 
Select and explain. 
A. in the stenotic or nonstenotic phase of the disease, B. in the stenotic phase only, C. as a rigid, nondistensible phenomenon, D. with gastric involvement
A: in the stenotic or nonstenotic phase of the disease
Answer: A: in the stenotic or nonstenotic phase of the disease 
Explanation: (a) Source: (Kasper, p. 1781) The string sign represents long areas of circumferential inflammation and fibrosis. It is seen in the stenotic and nonstenotic phase of Crohn's disease. In addition to the string sign, abnormal puddling of barium and fistulous tracts are other helpful x-ray signs of ileitis. Other radiologic findings in Crohn's disease include skip lesions, rectal sparing, small ulcerations, and fistulas.