let us assume that a supper earth is discovered in the other solar system. the supper earth has a steady rotation period and time-varying clouds. in addition, mountains and oceans are discovered on the surface of the supper earth. finally, the supper earth has a strong magnetic field with an unknown period. which one is the best reference for the wind measurements on the supper earth? (a) icebergs in oceans (b) mountains (c) magnetic field (d) clouds