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
About direct standardization all are true except - 
Select and explain. 
A. Age specific death rate is not needed, B. A standard population is needed, C. Population should be comparable, D. Two populations are compared
A: Age specific death rate is not needed
Answer: A: Age specific death rate is not needed 
Explanation: None