Find the relative maximum and minimum values. f(x,y) = x + y-12xy Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice. OA. The function has a relative maximum value of f(x,y) = at (x,y) = (Simplify your answers. Type exact answers. Type an ordered pair in the second answer box.) OB. The function has no relative maximum value. Select the correct choice below and, if necessary, fill in the answer boxes to complete your choice. OA. The function has a relative minimum value of f(x,y) = at (x,y) = (Simplify your answers. Type exact answers. Type an ordered pair in the second answer box.) OB. The function has no relative minimum value.