At What Point Is the Following Function a Local Maximum $f ( x , y ) = 3 - 10 x + 12 y - 5 x ^ { 2 } - 6 y ^ { 2 }$

Multiple Choice

At what point is the following function a local maximum? $f ( x , y ) = 3 - 10 x + 12 y - 5 x ^ { 2 } - 6 y ^ { 2 }$

A) $( 1,1 )$
B) $( - 1,1 )$
C) $( 3,1 )$
D) $( 0,1 )$
E) $( 1 , - 1 )$