The correct answer is: A. Chloroprene.
Chloroprene is a chemical compound with the formula $C_5H_5Cl$. It is a colorless liquid that is used to make neoprene, a synthetic rubber. Chloroprene is also used to make other chemicals, such as insecticides and herbicides.
Carbonyl chloride, also known as phosgene, is a chemical compound with the formula $COCl_2$. It is a colorless, poisonous gas that is used in the manufacture of pesticides and other chemicals. Phosgene is also used as a chemical weapon.
Nitrous oxide, also known as laughing gas, is a chemical compound with the
formula $N_2O$. It is a colorless, odorless gas that is used as an anesthetic and as a propellant in whipped cream cans. Nitrous oxide is also used as a recreational drug.Bleaching powder is a mixture of calcium hypochlorite and calcium chloride. It is a white, powdery substance that is used to bleach clothes and to disinfect surfaces. Bleaching powder is also used to make chlorine gas.
Chloroprene is the correct answer because it is a chemical compound that is used to make tear gas. Tear gas is a type of chemical weapon that is used to irritate the eyes and respiratory system. It is used to disperse crowds and to control riots.