The reference spheroid does not represent a completely accurate picture of the Earth's gravity because a. the lithosphere is generally weak. b. density is uniform within the Earth's layers. c. the surface of the Earth is not smooth. d. the asthenosphere is weak and allows for the lithosphere to rebound too quickly.

c. the surface of the Earth is not smooth.

Explanation:

The reference spheroid does not represent a completely accurate picture of the Earth's gravity because "the surface of the Earth is not smooth."

This is based on the fact that mass is distributed unevenly within the planet. The greater a concentration of earth mass has a gravitational pull on the earth surface, thereby generating bumps around the globe, this situation including some other factors such as mass shifts inside the earth, shifting and altering the weight of the ocean and atmosphere, among others, affect the shape of the earth.