Subtract the Polynomials and Simplify $\left( - 6 m ^ { 2 } - 7 m + 8 \right) - \left( 2 m ^ { 2 } - 5 m - 9 \right)$

Multiple Choice

Subtract the polynomials and simplify.
- $\left( - 6 m ^ { 2 } - 7 m + 8 \right) - \left( 2 m ^ { 2 } - 5 m - 9 \right)$

A) $- 8 m ^ { 2 } - 2 m + 17$
B) $- 8 m ^ { 2 } - 7 m ^ { 2 } + 5 m + 17$
C) $- 4 m ^ { 2 } - 12 m - 1$
D) $- 8 m ^ { 2 } - 12 m - 1$