What nerve agent was unleashed on a subway station in Tokyo by a Japanese cult?

• A. Tabun.
• B. Soman.
• C. Sarin.
• D. Cyclosarin.

Answer: (C)

This question hinges on identifying which nerve agent was used in a famous mass-casualty attack in Tokyo. The agent released by the Aum Shinrikyo cult in the 1995 subway attack is sarin, a highly toxic organophosphate nerve agent. Sarin disrupts the nervous system by inhibiting acetylcholinesterase, so acetylcholine builds up at nerve junctions. That overload triggers a cholinergic crisis with symptoms such as excessive secretions, tearing, sweating, urination, diarrhea, vomiting, pinpoint pupils, bronchospasm, and breathing difficulties. The rapid and widespread effects made sarin a clear choice for a deliberate attack intended to affect many people quickly, leading to numerous injuries and several deaths and prompting an extensive public health response.

The other agents listed are also nerve agents, but they were not the ones used in that incident, so they don’t fit the specific historical context of this event.