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
Magenta coloured tongue is seen in deficiency of 
Select and explain. 
A. Niacin, B. Riboflavin, C. Vitamin B12, D. All of the above
B: Riboflavin
Answer: B: Riboflavin 
Explanation: None