This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET Jan 2020, Subject name: Social & Preventive Medicine
Major source of cyanocobalamin vitamin is:- 
Select and explain. 
A. Animal only diet, B. Plant only diet, C. Sunlight, D. None
A: Animal only diet
Answer: A: Animal only diet 
Explanation: Vitamin B12 Synthesized exclusively by microbes. Dietary source is exclusively of animal origin Vitamin B12 deficiency clinical manifestations: Haematological: Megaloblastic anemia, Hypersegmentation of neutrophils. Neurological: Demyelination in peripheral nerves and spinal cord