Find the absolute maximum and minimum of f(x,y) = 4x + 3y within the domain x² + y² ≤ 25.

a) Max: (5,0) , Min: (-5,0)
b) Max: (0,5) , Min: (0,-5)
c) Max: (5,5) , Min: (-5,-5)
d) Max: (-5,-5) , Min: (5,5)