The rational function $f$ is defined by an equation in the form $f(x)=\frac{a}{x+b}$, where $a$ and $b$ are constants. The partial graph of $y=f(x)$ is shown, and it has a vertical asymptote at $x=-4$. If the graph passes through the point $(-6,-3)$, which equation could define function $g(x)$ if $g(x)=f(x-2)$?