If y= 0, for all (x, y)er', let j&,)=-y sin(1/y) ify#0. then at the point (0, 0), (a) f is not continuous (b) s is continuous but not differentiable (c) exists

if y= 0, For all (x, y)ER', let J&,)=-y sin(1/y) ify#0. Then at the point (0, 0), (A) f is NOT continuous (B) S is continuous but NOT differentiable (C) exists butdoes NOT exist Ox Oy (D) f is differentiable