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: Surgery
In ulcerative colitis, Ca arises from - 
Select and explain. 
A. Pseudopolyps, B. Dysplastic sites, C. Familial polyposis, D. Multiple adenomatous polyp
B: Dysplastic sites
Answer: B: Dysplastic sites 
Explanation: None