This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition, Subject name: Medicine
[{'content': 'Schilling test is done for ? \nSelect and explain. \nA. Vitamin B12 deficiency, B. Folic acid deficiency, C. Vitamin B6 deficiency, D. Vitamin D deficiency', 'role': 'user'}, {'content': 'Answer: A \nExplanation: schilling test to determine whether there is B12 malabsorption and if so where is it occurring Ref Harrison 20th edition pg 78', 'role': 'assistant'}]