Which equation does the function $y=e^{-6t}$ satisfy?

$y^{\text{'}\text{'}}-y^{\text{'}}-42y=0$

$y^{\text{'}\text{'}\text{'}}+y^{\text{'}}+3y=0$

$y^{\text{'}\text{'}}+y^{\text{'}}-42y=0$

$y^{\text{'}\text{'}}-3y^{\text{'}}+42y=0$