Explanation: GPS (Global Positioning System) satellites are specifically designed to provide continuous global coverage for navigation. They operate in Medium Earth Orbit (MEO) at an altitude of approximately 20,200 kilometers (12,550 miles). The correct description in **A) They are in six orbital planes equally spaced and inclined about 55 degrees to the equator,** accurately reflects this design. The six orbital planes, with satellites distributed within them, ensure that a minimum number of satellites (typically 4-8) are always "visible" above the horizon from almost any point on Earth. The 55-degree inclination allows for excellent coverage across most latitudes, including areas far from the equator, which would be poorly served by an equatorial orbit. This specific orbital geometry is crucial for the trilateration process used by receivers to calculate precise positions. **B) They are in four orbital planes spaced 90 degrees in a polar orbit,** is incorrect because GPS uses six planes, not four, and the inclination is 55 degrees, not a polar (90-degree) orbit. **C) They are in a geosynchronous orbit equally spaced around the equator,** is incorrect. Geosynchronous (specifically geostationary) satellites appear stationary relative to a point on the equator. GPS satellites are in MEO and continuously move relative to the Earth's surface, which is necessary for the geometric diversity required for accurate 3D positioning. **D) They are in eight orbital planes at an altitude of approximately 1,000 miles,** is incorrect. GPS uses six planes, not eight, and its altitude is much higher (MEO, ~12,550 miles), not the Low Earth Orbit (LEO) described by 1,000 miles.