The equilibrium constant for the given reaction is 100 $N_2 +2O_2 \rightleftharpoons 2NO_2$ What is the equilibrium for the reaction given below : $NO_2 \rightleftharpoons \large\frac{1}{2}$$N_2+O_2$

Question

$$\begin {array} {1 1} (1)\;10 & \quad (2)\;1 \\ (3)\;0.1 & \quad (4)\;0.01 \end {array}$$