Answer:
Clock on the satellite is slower than the one present on the earth = 29.376 s
Given:
Distance of satellite from the surface, d = 250 km
Explanation:
Here, the satellite orbits the earth in circular motion, thus the necessary centripetal force is provided by the gravitation force and is given by:

where
v = velocity of the satellite
R = radius of the earth = 6350 km = 6350000 m
G = gravitational constant = 
M = mass of earth = 
Therefore, the above eqn can be written as:

Now, for relativistic effects:

Now,
r = R + 250

Ratio of rate of satellite clock to surface clock:

Clock on the satellite is slower than the one present on the earth:

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Power = energy/time=20/4=5.0
The answer is "Force of gravity".