Explanation

A is correct because supersonic jets can cause ozone depletion by affecting the stratospheric ozone layer. B is incorrect because SO2 pollution relates to different atmospheric processes and layers. C is incorrect because O2 is a major component of the atmosphere and not specifically targeted for thinning by this mechanism. D is incorrect because CO2 is a greenhouse gas, but the primary concern regarding supersonic jets' direct impact on atmospheric layers is ozone depletion.