If the Following Defines a One-To-One Function, Find Its Inverse $f(x)=8 x^{2}-4$

Multiple Choice

If the following defines a one-to-one function, find its inverse. If not, write "Not one-to-one."
- $f(x) =8 x^{2}-4$

A) Not one-to-one
B) $f^{-1}(x) =\sqrt{\frac{x+4}{8}}$
C) $f^{-1}(x) =\frac{x+4}{8}$
D) $f^{-1}(x) = \pm \sqrt{\frac{x+4}{8}}$