Write a Linear Factorization of the Function $$f ( x ) = 9 x ^ { 3 } + 9 x$$

Multiple Choice

Write a linear factorization of the function.
- $$f ( x ) = 9 x ^ { 3 } + 9 x$$

A) $f ( x ) = 9 x ( x + i ) ^ { 2 }$
B) $f ( x ) = x ( x + 9 i ) ( x - i )$
C) $f ( x ) = 9 x ( x + 1 ) ^ { 2 }$
D) $f ( x ) = 9 x ( x + i ) ( x - i )$