The organophosphate insecticides were developed in which country during World War II as a substitute for nicotine:

Correct option is D

Organophosphate insecticides are synthetic chemicals widely used to control insect pests in agriculture and public health. They function primarily by inhibiting the enzyme acetylcholinesterase, which is essential for proper nervous system function in insects (and also in humans at toxic levels).
�� Historical Background:
· During World War II, Germany pioneered the development of organophosphates.
· German chemists, particularly Dr. Gerhard Schrader, were originally researching new chemical warfare agents.
· Schrader and his team at IG Farben discovered organophosphate compounds with potent neurotoxic effects.
· Some of these compounds, like Tabun and Sarin, were classified as nerve agents for warfare.
· However, milder derivatives were later adapted for agricultural use as substitutes for nicotine-based insecticides (e.g., nicotine sulfate), which were natural and costly.
· The commercial versions—like parathion, malathion, and diazinon—were introduced later after the war.