PLEASE HELP!!! ASAP!!!

Which expression is equivalent to [tex](m^{8} n^{-4} )\frac{1}{4}[/tex] ?

[tex]\frac{m^{2} }{n}[/tex]

[tex]\frac{1}{mn}[/tex]

[tex]m^{4} n[/tex]

[tex]mn[/tex]