This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
Which of the following insecticides is a natural product 
Select and explain. 
A. Dieldrin, B. Pyrethrum, C. Parathion, D. Carbaryl
B: Pyrethrum
Answer: B: Pyrethrum 
Explanation: Insecticides are substances used to kill insects. They are contact poison, stomach poisons, fumigants. Contact poisons are fuher classified into natural and synthetic. Examples of natural contact poisons are pyrethrum, rotenone, derris, nicotine, mineral oils. Pyrethrins are derived from Chrysanthemum. Park's Textbook of Preventive and Social Medicine, 25th Edition, Pg 843