Explanation

Option A is correct because photochemical smog is primarily composed of ozone, peroxyacetyl nitrate, and nitrogen dioxide. Option B is incorrect because it includes smoke instead of the key components like ozone or $ ext{NO}_2$. Option C is incorrect because $ ext{CO}_2$ is not a primary component listed for this type of smog. Option D is incorrect because while hydrocarbons and ozone are present, $ ext{SO}_2$ is less characteristic than $ ext{NO}_2$ in the main mixture.