Find the Requested Partial Derivative $$( \partial w / \partial z ) _ { x , y } \text { at } ( x , y , z , w ) = ( 1,2,9,266 ) \text { if } w = x ^ { 2 } + y ^ { 2 } + z ^ { 2 } + 10 x y z$$

Multiple Choice

Find the requested partial derivative.
- $$( \partial w / \partial z ) _ { x , y } \text { at } ( x , y , z , w ) = ( 1,2,9,266 ) \text { if } w = x ^ { 2 } + y ^ { 2 } + z ^ { 2 } + 10 x y z$$

A) 28
B) 33
C) 38
D) 48