Ozone is gaseous " secondary " air pollutant,because:-

Question

$\begin{array}{1 1}(a)\;\text{It is not an important pollutant}\\(b)\;\text{It causes secondary effects on plants & animals}\\(c)\;\text{It is formed by the oxides of nitrogen in sunlight & warm temperature}\\(d)\;\text{It is formed by the oxidation of }O_2\text{ in atmosphere}\end{array}$