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: Social & Preventive Medicine
[{'content': 'Birth weight of all 10 babies born an in a nursing home on a day was 2.7 kg. Standard deviation is - \nSelect and explain. \nA. 0, B. 1, C. 0. 27, D. 2.7', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Standard deviation is a measure of dispersion from central value.\nIn the question, there is only one central value (2.7 Kg) as all 10 babies have same weight. Thus, there is no dispersion.', 'role': 'assistant'}]