Find the Inflection Point(s) Of $f ( x ) = \frac { 2 } { 3 } x ^ { 3 } - 7 x ^ { 2 } + 24 x - 16$

Multiple Choice

Find the inflection point(s) of $f ( x ) = \frac { 2 } { 3 } x ^ { 3 } - 7 x ^ { 2 } + 24 x - 16$ .

A) $\left( \frac { 7 } { 2 } , \mathrm { f } \left( \frac { 7 } { 2 } \right) \right.$
B) (2, f (2) ) and (6, f (6) )
C) (56, f (56) )
D) (3, f (3) ) and (4, f (4) )
E) $\left( \frac { 2 } { 7 } , \mathrm { f } \left( \frac { 2 } { 7 } \right) \right.$