An electron starting from rest has a velocity that increases linearly with time i.e $v= kt$ where $k=2\;m\;s^{-2}$. The distance covered in the first 3 second is
$\begin{array}{1 1} (A) \;9\;m \\ (B) \;16\;m \\ (C)\;27\;m \\ (D)\;36\;m \end{array}$