Both a Function and Its Derivative Are Given $f ( x ) = x - 9 x ^ { 2 / 3 } + 7 \quad f ^ { \prime } ( x ) = \frac { x ^ { 1 / 3 } - 6 } { x ^ { 1 / 3 } }$

Multiple Choice

Both a function and its derivative are given. Use them to find all critical numbers. $f ( x ) = x - 9 x ^ { 2 / 3 } + 7 \quad f ^ { \prime } ( x ) = \frac { x ^ { 1 / 3 } - 6 } { x ^ { 1 / 3 } }$

A) $x = 0$
B) $x = 216$
C) $x = 0 , x = - 101$
D) $x = 0 , x = 216$
E) $x = - 101 , x = 216$