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: Pathology
The clinical combination of dermatitis, diarrhoea, and dementia resulting from a deficiency of niacin is referred to as: 
Select and explain. 
A. Beriberi, B. Marasmus, C. Pellagra, D. Rickets
C: Pellagra
Answer: C: Pellagra 
Explanation: Deficiencies of niacin produce pellagra, a disease that is characterized by the triad of dementia, dermatitis (“glove” or “necklace” distribution), and diarrhoea.