Find the Least Common Denominator of the Rational Expressions $\frac { 3 } { x ^ { 2 } + 3 x }$

Multiple Choice

Find the least common denominator of the rational expressions.
- $\frac { 3 } { x ^ { 2 } + 3 x }$ and $\frac { 9 } { x ^ { 2 } + 9 x + 18 }$

A) $x ( x - 3 ) ^ { 2 }$
B) $x ( x + 3 ) ^ { 2 } ( x + 6 )$
C) $x ( x - 3 ) ( x + 6 )$
D) $x ( x + 3 ) ( x + 6 )$