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
Which of the following is preferred in an elderly women having macrocytic anaemia with early signs of neurological deficit? 
Select and explain. 
A. Folic acid, B. Hydroxycobalamine, C. Erythropoietin, D. Iron dextran
B: Hydroxycobalamine
Answer: B: Hydroxycobalamine 
Explanation: None