This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Pathology
Causes of Vit. B12 deficiency megaloblastic anemia- 
Select and explain. 
A. Fish tap worm infestation, B. Dilantin therapy, C. Gastrectomy, D. Ileal resection
A: Fish tap worm infestation
Answer: A: Fish tap worm infestation 
Explanation: Fish tapeworm competes with cells in the ilium for vitamine B12 there by causing its defficiencyin the body. Reference:Exam preparatory manual for UGs by Ramdas Nayak Page no.:256