(2) The increasing interval of the function $f(x)=\log _{\frac{1}{2}}\left(-x^{2}-2 x+3\right)$ is $(\quad)$.
(A) $(-3,-1)$
(B) $[-1,1)$
(C) $(-3,-1]$
(D) $(-1,1)$
(2) B Hint: Method 1: From $-x^{2}-2 x+3>0$, we get $-30$, we get $-3<x<1 . f^{\prime}(x)=\log _{\frac{1}{2}} \mathrm{e} \cdot$ $\frac{-2(x+1)}{(x-1)(x+3)} \geqslant 0$ we get $x+1 \geqslant 0$, which means $x \geqslant-1$. Therefore, the increasing interval of the function $f(x)=$ $\log _{\frac{1}{2}}\left(-x^{2}-2 x+3\right)$ is $[-1,1)$. Hence, the answer is B.