Add or Subtract as Indicated $$\left( 4 x ^ { 7 } + 9 x ^ { 6 } - 6 x \right) + \left( 9 x ^ { 7 } + 8 x ^ { 6 } + 4 x \right)$$

Multiple Choice

Add or subtract as indicated. Express the answer as a single polynomial in standard form.
- $$\left( 4 x ^ { 7 } + 9 x ^ { 6 } - 6 x \right) + \left( 9 x ^ { 7 } + 8 x ^ { 6 } + 4 x \right)$$

A) $13 x + 17 x ^ { 7 } - 2 x ^ { 6 }$
B) $13 x ^ { 7 } + 17 x ^ { 6 } - 2 x$
C) $3 x ^ { 7 } + 12 x ^ { 6 } + 13 x$
D) $28 x ^ { 14 }$