Answer:
C
Explanation:
This is because it is a liquid
In order to achieve stable circular gravitational and centrifugal force must be in balance.

This relationship tells closer the closser your orbit is to the surface of the planet the faster you have to go. Which makes sense because the closer you are to the planet the stronger gravitational force gets.
Answer:
The average speed of an object is defined as the distance traveled divided by the time elapsed. Velocity is a vector quantity, and average velocity can be defined as the displacement divided by the time.