This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vitamins and Minerals, Subject name: Biochemistry
Which of the following vitamin deficiency causes pellagra? 
Select and explain. 
A. Thiamine, B. Ascorbic acid, C. Nicotinic acid, D. Cyanocobalamine
C: Nicotinic acid
Answer: C: Nicotinic acid 
Explanation: Ans. c (Nicotinic acid). (Ref. Harrison, Medicine, 14th ed., 463)NIACIN# Function: CoA enzyme in redox reactions.# 1 mg of niacin is formed from 60 mg of tryptophan.# Deficiency: Pellagra (diarrhea, dermatitis, dementia and death if untreated).# Hartnup disease, malignant carcinoid syndrome and INH therapy may also cause niacin deficiency.