This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
In clinical practice to label remission in the case of ulcerative colitis, all the features are needed, EXCEPT: 
Select and explain. 
A. Stool frequency <3 /day, B. No bleeding, C. No Urgency, D. Normal looking mucosa in endoscopy
D: Normal looking mucosa in endoscopy
Answer: D: Normal looking mucosa in endoscopy 
Explanation: In clinical practice, 'remission' mean a stool frequency <=3/day with no bleeding and no urgency. Sigmoidoscopy to confirm mucosal healing is generally unnecessary. Ref: Journal of Crohn's and Colitis (2012) 6, 965-990