Consider the following unit step function.

The Laplace transform of this function is

1. $\dfrac{e^{-3s}}{s} \\$
2. $\dfrac{e^{-3s}}{s^2} \\$
3. $\dfrac{e^{-3s}}{3s} \\$
4. $\dfrac{e^{-6s}}{s}$