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
[{'content': 'The best test to detect iron deficiency anaemia in a community with Iwo prevalence of iron deficiency is - \nSelect and explain. \nA. PCV, B. Serum iron, C. Serum ferritin, D. Iron binding capacity', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]