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: Surgery
Primary sclerosing cholangitis is associated with 
Select and explain. 
A. Ulcerative cholangitis, B. Retroperitoneal fibrosis, C. Reidel's thyroiditis, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: Features of ulcerative colitis in case of PSC(70%).PSC may be associated with retroperitoneal fibrosis,mediastinal fibrosis,Riedel's thyroiditis,orbital pseudotumour. Reference:SRB's manual of surgery,5th edition,page no:658.