$x = 8 t \sin s , y = 8 t \cos s$

Multiple Choice

$\text { Find } \frac { \partial w } { \partial s } \text { using the appropriate Chain Rule for } w = x ^ { 2 } + y ^ { 2 } + z ^ { 2 } \text { where }$ $x = 8 t \sin s , y = 8 t \cos s$ , and $z = 8 s t ^ { 2 }$

A) $64 s t ^ { 4 }$
B) $128 s ^ { 4 } t$
C) $16 s ^ { 4 } t$
D) $1285 t ^ { 4 }$
E) $16 s t ^ { 4 }$