Perform the Indicated Operations $\left( x ^ { 2 } - 4 x - 8 \right) + \left( 8 x ^ { 2 } - 7 x - 6 \right) - \left( 5 x ^ { 2 } - 4 x - 6 \right)$

Multiple Choice

Perform the indicated operations. $\left( x ^ { 2 } - 4 x - 8 \right) + \left( 8 x ^ { 2 } - 7 x - 6 \right) - \left( 5 x ^ { 2 } - 4 x - 6 \right)$

A) $- 4 x ^ { 2 } - 7 x + 8$
B) $4 x ^ { 2 } + 7 x - 8$
C) $4 x ^ { 2 } - 7 x + 8$
D) $4 x ^ { 2 } - 7 x - 8$