Perform the Indicated Operation $\left( 9 x ^ { 3 } + 9 x ^ { 2 } + 4 x + 6 \right) + \left( 4 x ^ { 3 } + 2 x + 8 \right)$

Multiple Choice

Perform the indicated operation.
- $\left( 9 x ^ { 3 } + 9 x ^ { 2 } + 4 x + 6 \right) + \left( 4 x ^ { 3 } + 2 x + 8 \right)$

A) $13 x ^ { 3 } + 9 x ^ { 2 } + 6 x + 14$
B) $13 x ^ { 3 } + 11 x ^ { 2 } + 8 x + 6$
C) $4 x ^ { 3 } + 11 x ^ { 2 } + 12 x + 6$
D) $13 x ^ { 3 } + 6 x + 14$