Some reactions of $NO _2$ relevant to photochemical smog formation are

Identify $A , B , X$ and $Y$
Match the following:
In the following, \( [x] \) denotes the greatest integer less than or equal to \( x \). 
Choose the correct answer from the options given below:
For x < 0:
f(x) = ex + ax
For x ≥ 0:
f(x) = b(x - 1)2
There is a number of factors that contribute to the pollution of the environment. Some of the major causes of atmospheric pollution are given below -