Find the Derivative of the Function at P0 in the Direction

Multiple Choice

Find the derivative of the function at P0 in the direction of u.
- $$f ( x , y ) = \tan ^ { - 1 } \frac { - 3 x } { y } , \quad P _ { 0 } ( - 7 , - 8 ) , \quad \mathbf { u } = 12 \mathbf { i } - 5 \mathbf { j }$$

A) $\frac { 393 } { 6565 }$
B) $\frac { 456 } { 6565 }$
C) $\frac { 27 } { 505 }$
D) $\frac { 477 } { 6565 }$