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: Social & Preventive Medicine
One mg. of Niacin is produced by.......................... mg. of Tryptophan- 
Select and explain. 
A. 22, B. 37, C. 55, D. 60
D: 60
Answer: D: 60 
Explanation: Ans. is 'd' i.e., 60 About 60 mg of tryptophan is required to result in I mg of niacin.