Find the Derivative Of $f ( x ) = 2 x \left( 4 x ^ { 2 } + 1 \right) ^ { 7 }$

Multiple Choice

Find the derivative of $f ( x ) = 2 x \left( 4 x ^ { 2 } + 1 \right) ^ { 7 }$

A) $\left( 112 x ^ { 2 } + 2 \right) \left( 4 x ^ { 2 } + 1 \right) ^ { 6 }$
B) $\left( 120 x ^ { 2 } + 2 \right) \left( 4 x ^ { 2 } + 1 \right) ^ { 7 }$
C) $\left( 120 x ^ { 2 } + 2 \right) \left( 4 x ^ { 2 } + 1 \right) ^ { 6 }$
D) $112 x ^ { 2 } \left( 4 x ^ { 2 } + 1 \right) ^ { 6 }$