1. Let $A=[-2,4), B=\left\{x \mid x^{2}-a x-4 \leqslant 0\right\}$. If $B \subseteq A$, then the range of real number $a$ is ( ).
(A) $[-3,0)$
(B) $[-2,0)$
(C) $[0,2)$
(D) $[0,3)$
$\begin{array}{l}\text {-,1. D. } \\ \text { Given } f(x)=x^{2}-a x-4 \text { opens upwards, and } \\ \left\{x \mid x^{2}-a x-4 \leqslant 0\right\} \subseteq[-2,4), \\ \text { we know } f(-2) \geqslant 0, f(4)>0 \\ \Rightarrow a \in[0,3) . \\\end{array}$