Which of the following is the most toxic nerve agent?

VX is recognized as one of the most toxic nerve agents due to its high potency and the manner in which it disrupts the nervous system. It inhibits the enzyme acetylcholinesterase, leading to an accumulation of the neurotransmitter acetylcholine at nerve synapses. This results in continuous stimulation of muscles and glands, ultimately leading to respiratory failure and potentially death.

Compared to other nerve agents, VX has a longer lasting effect, and even small doses can be lethal, making it particularly dangerous in both battlefield and terrorist scenarios. The toxicity of VX is often measured in micrograms, indicating that even minute quantities can have severe consequences.

While Sarin, Novichok, and Tabun are also classified as nerve agents and possess significant toxic properties, VX's level of lethality and its characteristics in chemical warfare applications have led to its distinction as one of the most toxic agents known.