For the reaction
`N_2 (g) + O_2 (g) ``overset(rightarrow)(leftarrow)`` 2NO (g)`
the equilibrium constant is` K_1`. The equilibrium constant is `K_2` for the reaction ,
`2NO(g) + O_2 (g) ``overset(rightarrow)(leftarrow)`` 2NO_2` (g).
What is K for the reaction,
`NO_2 (g)``overset(rightarrow)(leftarrow)`` 1/2N_2(g)+ O_2 (g)`-

Options

A. `1/(2k_1k_2)`
B. `1/(4k_1k_2)`
C. `[1/(k_1k_2)]^(1/2)`
D. `1/(k_1k_2)`