This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunomodulators, Subject name: Pharmacology
[{'content': 'What is true regarding sulfasalazine? \nSelect and explain. \nA. Active moiety is 5 amino salicylic acid in ulcerative colitis, B. Inactive moiety is 5 amino salicylic acid in ulcerative colitis, C. Inactive moiety in rheumatoid ahritis is Sulfapyridine, D. It gets activated in the stomach', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Around 90% of a dose of sulfasalazine reaches the colon, where most of it is metabolized by bacteria into sulfapyridine and mesalazine (also known as 5-aminosalicylic acid or 5-ASA).5 ASA is the active moiety produced in the colon in U.Colitis.In rheumatoid ahritis the active moiety is sulphapyridine.Ref: Katzung 13th ed. Pg: 1072', 'role': 'assistant'}]