Compute All First-Order Partial Derivatives of the Given Function $f ( x , y ) = ( 4 x + 2 y ) ^ { 4 }$

Multiple Choice

Compute all first-order partial derivatives of the given function. $f ( x , y ) = ( 4 x + 2 y ) ^ { 4 }$

A) $f _ { x } = 16 ( 4 x + 2 y ) ^ { 5 }$ , $f _ { y } = 8 ( 4 x + 2 y ) ^ { 5 }$
B) $f _ { x } = 16 ( x + 2 y ) ^ { 3 }$ , $f _ { y } = 8 ( 4 x + 2 ) ^ { 3 }$
C) $f _ { x } = 16 ( 2 y ) ^ { 3 }$ , $f _ { y } = 8 ( 4 x ) ^ { 3 }$
D) $f _ { x } = 16 ( 4 x + 2 y ) ^ { 3 }$ , $f _ { y } = 8 ( 4 x + 2 y ) ^ { 3 }$