Why Is Earth's Gravitational Field NOT Smooth

Why is Earth's gravitational field NOT smooth?

A) Gravitational fields are never smooth due to changes in the shape of the planets.
B) Earth is close to the Sun,which pulls on the gravitational field and causes it to be misshapen.
C) The density of materials on Earth is not uniform and the surface contains changes in topography.
D) The gravitational field is much lower for any area that is covered in water and thus is different over land versus water.