Determine All Critical Points for the Function $$f ( x ) = 20 x ^ { 3 } - 3 x ^ { 5 }$$

Multiple Choice

Determine all critical points for the function.
- $$f ( x ) = 20 x ^ { 3 } - 3 x ^ { 5 }$$

A) $x = 2$
B) $x = - 2$
C) $x = - 2$ and $x = 2$
D) $x = 0 , x = - 2$ , and $x = 2$