Find the Largest Open Interval Where the Function Is Changing $y=\left(x^{2}-9\right)^{2}$

Multiple Choice

Find the largest open interval where the function is changing as requested.
-Increasing $y=\left(x^{2}-9\right) ^{2}$

A) $(3, \infty)$
B) $(-3,0)$
C) $(-3,3)$
D) $(-\infty, 0)$