Answer
$f(x)=\frac{-2x}{x^2-4}$ matches the graph labeled (b).
Work Step by Step
The vertical asymptotes are:
$x^2-4=0$
$x^2=4$
$x=\pm2$
The degree of the denominator is greater than the degree of the numerator. The horizontal asymptote is the line $y=0$, that is, the x-axis.
