This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Air, Light, Sound, Housing, Radiation, Waste Disposal, Subject name: Social & Preventive Medicine
[{'content': 'Maximum permissible dose of radiation exposure for human beings is:- \nSelect and explain. \nA. 1 rad per person per year 1 rad per person per year, B. 5 rad per person per year, C. 10 rad per person per year, D. 50 rad per person per year', 'role': 'user'}, {'content': "Answer: B \nExplanation: Radiation exposure: Maximum permissible radiation exposure for humans: 5 rad per person per year ; in pregnancy = 0.5 rad/p/yr. Total natural radiation received by human = 0.1 rad/p/yr. State receiving highest solar radiation is Rajasthan. Thickness of lead apron to prevent exposure - >= 0.5 mm. Radiation exposure in Chernobyl tragedy - Cs, I2 and Sr. Occupational exposure - Effective dose shouldn't exceed 20 mSv/year. General Public exposure - Effective dose shouldn't exceed 1 mSv/year.", 'role': 'assistant'}]