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 one of the following is a stomach poison for the larvae of insects of medical importance? 
Select and explain. 
A. DDT, B. Paris green, C. Pyrethrum, D. Antilarva oil
B: Paris green
Answer: B: Paris green 
Explanation: Insecticides are substances used to kill insects.
They are contact poisons,stomach poisons,fumigants. 
Stomach poisons are those which when ingested cause death of the insects. 
Examples are paris green and sodium flouride. DDT and pyrethrum are synthetic and natural contact poisons respectively. 
Parks textbook of preventive and social medicine.K Park.