Cone is shaped like triangle and cylinder is in pipe shaped. So, it's definately Not 'A' or 'C'.
Now Remaining is B - Ellipsoid & D - Torus. Torus is Doughnut in shape and it has only one axis to revolve. But don't create any egg shaped structure. Now B - Ellipsoid, If we rotate the ellipse on is X axis in 360'. Then it creates a UFO shape round. So, the answer is Ellipsoid.