This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
All are seen in carcinoid syndrome 
Select and explain. 
A. Diarrhoea, B. Constipation, C. Liver metastasis, D. 5-HT secretion
B: Constipation
Answer: B: Constipation 
Explanation: Carcinoid syndrome is a paraneoplastic syndrome comprising the signs and symptoms that occur secondary to carcinoid tumors. The syndrome includes flushing and diarrhea, and less frequently, hea failure, vomiting and bronchoconstriction. It is caused by endogenous secretion of mainly serotonin and kallikrein. Ref: Internet sources