$\text { Find the derivative of the function } f ( x ) = - 7 x ^ { 3 } + 4 x ^ { 2 } + 1 \text {. }$

Multiple Choice

$\text { Find the derivative of the function } f ( x ) = - 7 x ^ { 3 } + 4 x ^ { 2 } + 1 \text {. }$

A) $f ^ { t } ( x ) = - 14 x + 4 x ^ { 2 }$
B) $f ^ { t} ( x ) = - 14 x ^ { 2 } + 4 x$
C) $f ^ { t } ( x ) = - 7 x ^ { 2 } + 4 x ^ { 2 } + 1$
D) $f ^ { t } ( x ) = - 21 x ^ { 2 } + 8 x + 1$
E) $f ^ {t } ( x ) = - 21 x ^ { 2 } + 8 x$