Let f(x,y)=x⁽³⁾y- xy⁽⁴). Show that (0,0) is the only critical point of f(x,y).
a) The point (0,0) is the only critical point of f(x,y).
b) There are multiple critical points of f(x,y) other than (0,0).
c) The critical points of f(x,y) cannot be determined.
d) (0,0) is not a critical point of f(x,y).