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
Which of the following insecticides is a natural product ? 
Select and explain. 
A. Dieldrin, B. Pyrethnun, C. Parathion, D. Carbaryl
B: Pyrethnun
Answer: B: Pyrethnun 
Explanation: None