The correct answer is A. Tear gas.
Tear gas is a common name for a group of lachrymatory agents that irritate the eyes to cause tears, pain, and temporary blindness. It is used as a riot control agent and in self-defense.
Laughing gas is a common name for nitrous oxide, a gas that is used as an anesthetic and a recreational
drug. It is not a tear gas.Anaesthetic gas is a general term for any gas that is used to induce unconsciousness. It is not a tear gas.
Noble gas is a term for a group of elements that are chemically inert. They are not tear gases.