Express in Terms of I $\sqrt{-4}$ A) $2 \mathrm{i}$ B) $-\mathrm{i} \sqrt{2}$ C) $\pm 2$

Express in terms of i.
- $\sqrt{-4}$

A) $2 \mathrm{i}$
B) $-\mathrm{i} \sqrt{2}$
C) $\pm 2$
D) $-2 \mathrm{i}$