Add or Subtract as Indicated $$\left( 3 x ^ { 6 } - 5 x ^ { 3 } - 13 \right) - \left( 8 x ^ { 6 } + 8 x ^ { 3 } + 18 \right)$$

Multiple Choice

Add or subtract as indicated. Express the answer as a single polynomial in standard form.
- $$\left( 3 x ^ { 6 } - 5 x ^ { 3 } - 13 \right) - \left( 8 x ^ { 6 } + 8 x ^ { 3 } + 18 \right)$$

A) $- 49 x ^ { 9 }$
B) $- 5 x ^ { 6 } - 13 x ^ { 3 } + 5$
C) $- 5 x ^ { 6 } + 3 x ^ { 3 } + 5$
D) $- 5 x ^ { 6 } - 13 x ^ { 3 } - 31$