The correct answer is (d) 24 hours.
A geostationary satellite is a satellite that orbits the Earth at an altitude of 35,786 kilometers (22,236 miles). At this altitude, the satellite’s orbital period is the same as the Earth’s rotational period, which is 24 hours. This means that the satellite appears to be stationary in the sky, as seen from the Earth’s surface.
The other options are incorrect because they are not the orbital period of a geostationary satellite. Option (a) is 6 hours, which is the orbital period of a low-Earth orbit satellite. Option (b) is 12 hours, which is the orbital period of a medium-Earth orbit satellite. Option (c) is 18 hours, which is not a common orbital period for any type of satellite.
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