若 $f(-x)=f(x)(-\infty < x < +\infty)$, 且在 $(-\infty, 0)$ 内 $f^{\prime}(x)>0, f^{\prime \prime}(x) < 0$ ，则 $f(x)$ 在 $(0,+\infty)$ 内
$\text{A.}$ $f^{\prime}(x)>0, \quad f^{\prime \prime}(x) < 0$
$\text{B.}$ $f^{\prime}(x)>0, \quad f^{\prime \prime}(x)>0$
$\text{C.}$ $f^{\prime}(x) < 0, \quad f^{\prime \prime}(x) < 0$
$\text{D.}$ $f^{\prime}(x) < 0, \quad f^{\prime \prime}(x)>0$