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: Biochemistry
Beri-beri is caused due to the deficiency of: 
Select and explain. 
A. Thiamine, B. Pyridoxine, C. Ascorbic acid, D. Riboflavin
A: Thiamine
Answer: A: Thiamine 
Explanation: None