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 principal impact indicator in Iodine Deficiency disorders \nSelect and explain. \nA. Urinary Iodine Levels, B. Goitre assessment, C. Neonatal TSH levels, D. Salt Iodine Content', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Urinary Iodine Levels -\xa0principal impact indicator.\nNeonatal TSH levels - screening programme for hypothyroidism.', 'role': 'assistant'}]