Find the X Coordinates of All Relative Extreme Points Of f

Multiple Choice

Find the x coordinates of all relative extreme points of $f ( x ) = \frac { 2 } { 3 } x ^ { 3 } - 7 x ^ { 2 } + 24 x - 72$

A) x = -4, -3, 0
B) x = -4, -3
C) x = 3, 4
D) x = 2, 6
E) x = 0, 3, 4