This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
[{'content': '"Carbon credits" are issued in the terms of units of Ceified Emission Reduction (CER). Each CER is equivalent to - \nSelect and explain. \nA. 1 kg of CO2 reduction, B. 10 kg of CO2 reduction, C. 100 kg of CO2 reduction, D. 1 ton of CO2 reduction', 'role': 'user'}, {'content': 'Answer: D \nExplanation: The offset ceificates issued by the clean development mechanism (CDM) are the ceified emission reductions (CERs). Each CER is equivalent to one tonne of carbon dioxide (CO2) avoided or removed from the atmosphere. By using CERs, emissions are offset Ref: Internet', 'role': 'assistant'}]