设全集$U=\left\{\overline{)x\in N}x\ge 2\right\}$，集合$A=\left\{\overline{)x\in N⩾}{x}^2\ge 5\right\}$，则$C_{U}A=$

$\varnothing$ $\left\{2\right\}$ $\left\{5\right\}$ $\left\{2,5\right\}$