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: Pathology
What is true about ulcerative colitis? 
Select and explain. 
A. Involves rectum and then whole colon backwards, B. Involves only colon, C. Skip lesions seen, D. Ileum not involved
B: Involves only colon
Answer: B: Involves only colon 
Explanation: Ans. is 'b' i.e., Involves rectum and then whole colon backwards o Ulcerative colitis involves the rectum and extends proximally in a retrograde fashion to involve the entire colon (pancolitis) in more severe cases.