Determine the Open Intervals on Which the Graph Of $y = - 3 x ^ { 3 } + 8 x ^ { 2 } + 8 x - 5$

Multiple Choice

Determine the open intervals on which the graph of $y = - 3 x ^ { 3 } + 8 x ^ { 2 } + 8 x - 5$ is concave downward or concave upward.

A) concave downward on $( - \infty , \infty )$
B) concave downward on $\left( - \infty , \frac { 8 } { 9 } \right)$ ; concave upward on $\left( \frac { 8 } { 9 } , \infty \right)$
C) concave upward on $\left( - \infty , - \frac { 8 } { 9 } \right)$ ; concave downward on $\left( - \frac { 8 } { 9 } , \infty \right)$
D) concave downward on $\left( - \infty , - \frac { 8 } { 9 } \right)$ ; concave upward on $\left( - \frac { 8 } { 9 } , \infty \right)$
E) concave upward on $\left( - \infty , \frac { 8 } { 9 } \right)$ ; concave downward on $\left( \frac { 8 } { 9 } , \infty \right)$