Find values of $k$ if area of triangle is $4\; sq. units$ and vertices are $(-2, 0), (0, 4), (0, k)$

Question

$\begin{array}{1 1} 1 \;and\; -8 \\ 1\; and\; 8 \\ 0\; and\; -8 \\ 0\; and\; 8 \end{array} $