Examine the function $f(x,y)=x^3-6xy+y^3+8$ for relative extrema and saddle points.

relative minimum: $(2,2,0)$; relative maximum: $(0,0,8)$

saddle point: $(2,2,0)$; relative minimum: $(0,0,8)$

saddle point: $(0,0,8)$; relative minimum: $(2,2,0)$

relative minimum: $(0,0,8)$; relative maximum: $(2,2,0)$

saddle points: $(0,0,8),(2,2,0)$