What is the simplified form of 3a^4 b^-2 c^3

the choices are
(81a^4 c^3)/b^2
(81a^4)/(b^2 c^30
(3a^4)/(b^2 c3)
(3a^4 c^3)/b^2

The simplified form of 3a^4 b^-2 c^3 is (3a^4 c^3)/b^2