This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc., Subject name: Medicine
Which extra-intestinal symptom of IBD worsens with exacerbation of disease activity? 
Select and explain. 
A. Toxic megacolon, B. Ahritis, C. Primary sclerosing cholangitis, D. Uveitis
B: Ahritis
Answer: B: Ahritis 
Explanation: Toxic megacolon is an intestinal manifestation and hence is ruled out. Ahritis develops in 15-20% patients of I.B.D and it worsens with disease activity. Control of bowel inflammation will reduce the ahritis symptoms. Venous thromboembolism and erythema nodosum also worsens with disease activity. PSC may occur before symptoms of ulcerative colitis begin and may develop years after the proctocolectomy has been performed.