Correct Option: A

Supersonic jet causes pollution by thinning of O₃ layer. The simple chlorine-chlorine monoxide cycle can only occur at high altitudes where there are enough free oxygen atoms to allow the second step in the chain to run. A number of evidences have accumulated to show that these reactions are indeed destroying small amounts of ozone at about 40 km above Earth. Other families of radicals also participate in catalytic cycles that destroy ozone- nitrogen oxides released by supersonic jets.