I. The earth is not spherical but elliptical in shape
II. Variation in latitude and longitude
III. Rotation of the earth on its axis
IV. Variation in the density of the earth

On which combination of the above does the weight of an object vary on the earth's surface?

• A.I, II, III and IV
• B.II, III and IV only
• C.I, II and III only
• D.I and II only
• E.