This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutrition and health, Subject name: Social & Preventive Medicine
[{'content': 'Single most sensitive tool for evaluating the iron status is \nSelect and explain. \nA. Haemoglobin concentration, B. Serum ion concentration, C. Serum ferritin, D. Serum transferrin saturation', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Serum ferritin is the single most sensitive tool for evaluating the iron status.It reflects the size of Iron stores in the body. Values below 10 mcg/L indicate an absence of stored iron.Park 23e pg: 623', 'role': 'assistant'}]