How much work is done on a satellite in a circular orbit about Earth? Zero The gravity force on the satellite times the diameter of the orbit The mass of the satellite times the circumference of the orbit The weight of the satellite times the circumference of the orbit

a. Zero
b. The gravity force on the satellite times the diameter of the orbit
c. The mass of the satellite times the circumference of the orbit
d. The weight of the satellite times the circumference of the orbit