#### Answer

$H$

#### Work Step by Step

Take the square root of both sides to obtain:
$\sqrt{x^2}=\pm \sqrt{-20}
\\x = \pm \sqrt{4(-1)5}
\\x=\pm 2\sqrt{-1(5)}$
Since $\sqrt{-1}=i$, then the expression above simplifies to
$x=\pm 2i\sqrt5$
Thus, the answer is $H$.