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: Pathology
Most common site of gastrointestinal carcinoid is - 
Select and explain. 
A. Duodenum, B. Appendix, C. Ileo-Jejunum, D. Stomach
C: Ileo-Jejunum
Answer: C: Ileo-Jejunum 
Explanation: Answer- C. Ileo-JejunumCarcinoid tumors arise from the neuroendocrine cells (Argentaffin cells or Kulchitsky cells).The majority are found in GI tract, and more than,l0% in small intestine (jejunum & ileum).The tracheobronchial tree and lungs are the next common sites involved.