Find the Intervals of Increase and Decrease For $f ( x ) = 6 x ^ { 3 } + 9 x ^ { 2 } - 108 x - 2$

Multiple Choice

Find the intervals of increase and decrease for $f ( x ) = 6 x ^ { 3 } + 9 x ^ { 2 } - 108 x - 2$ .

A) Increasing on x $\le$ -2 and x $\ge$ 3, decreasing on - 2 $\le$ x $\le$ 3
B) Increasing on x < -3 and x > 2, decreasing on -3 < x < 2
C) Increasing on -3 < x < 2, decreasing on x < -3 and x > 2
D) Increasing on x < -2, decreasing on x > 3