Add or Subtract as Indicated $$\left( 6 x ^ { 2 } + 7 x + 12 \right) - \left( 3 x ^ { 2 } - 6 x - 7 \right)$$

Multiple Choice

Add or subtract as indicated. Express the answer as a single polynomial in standard form.
- $$\left( 6 x ^ { 2 } + 7 x + 12 \right) - \left( 3 x ^ { 2 } - 6 x - 7 \right)$$

A) $3 x ^ { 2 } + 10 x + 5$
B) $3 x ^ { 2 } + 13 x + 19$
C) $3 x ^ { 2 } + 13 x - 19$
D) $3 x ^ { 2 } + 13 x + 5$