已知集合 $A=\left\{x \mid x^{2}-x-2>0\right\}$, 则 $C_{R} A= $
$\text{A.}$ $\{x \mid-1 < x < 2\}$
$\text{B.}$ $\{x \mid-1 \leqslant x \leqslant 2\}$
$\text{C.}$ $\{x \mid x < -1\} \cup\{x \mid x>2\}$
$\text{D.}$ $\{x \mid x \leqslant-1\} \cup\{x \mid x \geqslant 2\}$