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: Medicine
Which of the following is most frequently associated with the typical form of carcinoid syndrome ? 
Select and explain. 
A. Foregut carcinoid, B. Midgut carcinoid, C. Hindgut carcinoid, D. None of the above
B: Midgut carcinoid
Answer: B: Midgut carcinoid 
Explanation: Midgut carcinoids are argentaffin-positive and have a high serotonin content. They most frequently cause the typical carcinoid syndrome when they metastasize. Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 3058