The monotone increasing interval of the function $f(x) = \ln(x^2 - 2x - 9)$ is A. $(-\infty, -2)$ B. $(-\infty, 1)$ C. $(1, +\infty)$ D. $(4, +\infty)$
The monotone increasing interval of the function $f(x) = \ln(x^2 - 2x - 9)$ is
A. $(-\infty, -2)$
B. $(-\infty, 1)$
C. $(1, +\infty)$
D. $(4, +\infty)$