$\text { Find the derivative of the algebraic function } f ( x ) = x \left( 3 - \frac { 4 } { x + 6 } \right) \text {. }$

Multiple Choice

$\text { Find the derivative of the algebraic function } f ( x ) = x \left( 3 - \frac { 4 } { x + 6 } \right) \text {. }$

A) $f ^ {t} ( x ) = \frac { 84 - 36 x + 3 x ^ { 2 } } { ( x + 6 ) ^ { 2 } }$
B) $f ^ { t } ( x ) = \frac { 84 + 36 x + 3 x ^ { 2 } } { ( x + 6 ) ^ { 2 } }$
C) $f ^ {t } ( x ) = \frac { 84 + 9 x + 3 x ^ { 2 } } { ( x + 6 ) ^ { 2 } }$
D) $f ^ {t} ( x ) = \frac { 84 - 36 x - 3 x ^ { 2 } } { ( x + 6 ) ^ { 2 } }$
E) $f ^ { t } ( x ) = \frac { 84 + 36 x - 3 x ^ { 2 } } { ( x + 6 ) }$