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
Percentage of para-para isomer in DDT is ? 
Select and explain. 
A. 20-30%, B. 40-50%, C. 60-70%, D. 70-80%
D: 70-80%
Answer: D: 70-80% 
Explanation: Ans. is 'd' i.e., 70-80% o DDT is an amorphous white powder. o Para-para isomer is the most active fraction ---> contains 70-80% of para-para isomers.