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 anaemia and posterior column dysfunction, the likely cause is - 
Select and explain. 
A. B1-deficit, B. B12-deficit, C. SSPE, D. Multiple selerosis
B: B12-deficit
Answer: B: B12-deficit 
Explanation: None