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.
- $$f ( x , y ) = 6 x - 7 y , \quad P _ { 0 } ( - 7 , - 2 ) , \quad u = 4 i - 3 j$$

A) $- \frac { 11 } { 5 }$
B) $\frac { 3 } { 5 }$
C) $\frac { 59 } { 5 }$
D) 9