This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous (Bio-Chemistry), Subject name: Biochemistry
Wernicke's encephalopathy occurs due to deficiency of 
Select and explain. 
A. Vitamin B1, B. Vitamin B2, C. Vitamin B6, D. Vitamin B12
A: Vitamin B1
Answer: A: Vitamin B1 
Explanation: (A) Vitamin B1 # Dry Beriberi involves both the peripheral and the central nervous systems.> Peripheral nerve involvement is typically asymmetric motor & sensory neuropathy with pain, paresthesias& loss of reflexes.> The legs are affected more than the arms. Central nervous system involvement results in Wernicke-Korsakoff syndrome.> Wernicke's encephalopathy consists of nystagmus progressing to ophthalmoplegia, truncal ataxia & confusion> Koraskoff's syndrome includes amnesia, confabulation, and impaired learning.