Which statement best describes how to determine whether f(x) = 9 – 4x^2 is an odd function?

Determine whether 9 – 4(–x)^2 is equivalent to 9 – 4x^2.

Determine whether 9 – 4(–x^2) is equivalent to 9 + 4x^2.
Determine whether 9 – 4(–x)^2 is equivalent to –(9 – 4x^2).

Determine whether 9 – 4(–x^2) is equivalent to –(9 + 4x^2).