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: Medicine
65-year-old man presents with anemia, posterior columan dysfunction, and planter extensor. Which of the following is the likely cause 
Select and explain. 
A. Tabes dorsalis, B. Frederich's ataxia, C. Vitamin B1 deficiency, D. Vitamin B 12 deficiency
D: Vitamin B 12 deficiency
Answer: D: Vitamin B 12 deficiency 
Explanation: Ans. is 'd' i.e., Vitamin B12 deficiency