Answer:
[tex]\text{A. 8}i[/tex]
Step-by-step explanation:
The math constant [tex]i[/tex] represents [tex]\sqrt{-1}[/tex]. Because [tex]\sqrt{a\cdot b}=\sqrt{a}\cdot\sqrt{b}[/tex], we can rewrite the equation given the problem as [tex]\sqrt{-64}=\sqrt{64}\cdot \sqrt{-1}=\boxed{8i}[/tex].
