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
Not a pyTethram derivative? 
Select and explain. 
A. Cypermethrin, B. Penncthrin, C. DDT, D. Resmethrin
C: DDT
Answer: C: DDT 
Explanation: Ans. is 'c' i.e., DDT