This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'About direct standardization all are true except \nSelect and explain. \nA. Age specific death rate is not needed, B. A standard population is needed, C. Population should be comparable, D. Two populations are compared', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ref: Park&;s 23rd edition pg 58 Direct standardisation involves selection of a standard population which is defined as the one for which the number in each age and sex group are known. hence we require age specific death rate for comparison.', 'role': 'assistant'}]