$NO+O_3\rightarrow NO_2+O_2,O_3+hv\rightarrow x+y,NO_2+O\rightarrow z+x$.Net reaction :$A(O_3)+hv\rightarrow BO_2$.$B-A$ is

Question

$\begin{array}{1 1}(a)\;1\\(b)\;2\\(c)\;4\\(d)\;-1\end{array}$