This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Proteins and Amino Acids, Subject name: Biochemistry
5 HIAA in urine is due to: 
Select and explain. 
A. Pheochromocytoma, B. Carcinoid syndrome, C. Phenyl ketonuria, D. Alkaptonuria
B: Carcinoid syndrome
Answer: B: Carcinoid syndrome 
Explanation: Ans. B. Carcinoid syndromeIn Pheochromocytoma VMA is excreted in excess in urine.In Carcinoid syndrome 5 HIAA is excreted in excess in urine.In PKU Phenyl Ketones like Phenyl acetate and Phenyl Pyruvate is excreted in urine.In Alkaptonuria Homogentisate is excreted in urine.