观察$\left(x^2\right)`=2x$，$\left(x^4\right)`=4x^3$，$\left(\cos x\right)`=-\sin x$，由归纳推理可得：若定义在$R$上的函数$f\left(x\right)$满足$f\left(-x\right)=f\left(x\right)$，记$g\left(x\right)$为$f\left(x\right)$的导函数，则$g\left(-x\right)=$（）

A．

$f\left(x\right)$

B．

$-f\left(x\right)$

C．

$g\left(x\right)$

D．

$-g\left(x\right)$