Consider an $LTI$ system with impulse response $h(t)=e^{-5t}u(t)$ . If the output of the system is $y(t)=e^{-3t}u(t)-e^{-5t}u(t)$  then the input, $x(t)$, is given by
1. $e^{-3t}u(t)$
2. $2e^{-3t}u(t)$
3. $e^{-5t}u(t)$
4. $2e^{-5t}u(t)$