This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Small intestine, Subject name: Surgery
All of the following are true about carcinoid tumors except: 
Select and explain. 
A. Ileum is the commonest site in GIT, B. Commonest site for malignant carcinoid is distal ileum, C. Elevated urinary 5-HIAA is diagnostic of carcinoid syndrome, D. Commonest valvular disease in carcinoid syndrome is pulmonary stenosis
D: Commonest valvular disease in carcinoid syndrome is pulmonary stenosis
Answer: D: Commonest valvular disease in carcinoid syndrome is pulmonary stenosis 
Explanation: o Bronchus is the commonest site for carcinoids & in the GIT, ileum is the commonest siteo Ileum is the commonest site for malignant carcinoidso The commonest valvular lesion seen in carcinoids is tricuspid regurgitation