Answer:
C
Step-by-step explanation:
Using the rule of radicals
[tex]\sqrt{a}[/tex] × [tex]\sqrt{b}[/tex] ⇔ [tex]\sqrt{ab}[/tex]
noting that [tex]\sqrt{-1}[/tex] = i
[tex]\sqrt{-80}[/tex]
= [tex]\sqrt{16(5)(-1)}[/tex]
= [tex]\sqrt{16}[/tex] × [tex]\sqrt{5}[/tex] × [tex]\sqrt{-1}[/tex]
= 4i[tex]\sqrt{5}[/tex] → C
