The Laplace transform of a continuous-time signal $x(t)$ is $X(s)=\frac{5-s}{s^{2}-s-2}$. If the Fourier transform of this signal exists, then $x(t)$ is
- $e^{2 t} u(t)-2 e^{-t} u(t)$
- $-e^{2t} u(-t)+2 e^{-t} u(t)$
- $-e^{2 t} u(-t)-2 e^{-t} u(t)$
- $e^{2 t} u(-t)-2 e^{-t} u(t)$