Final answer:
GPS units are used by various groups and are accurate to within 10 meters. They have been used to determine the height of Mt. Everest as 8850 meters or 29,035 feet above sea level. So, the correct answer is option a.
Step-by-step explanation:
Global Positioning System (GPS) units are used by various groups, including the military, surveyors, and agriculturists to accurately determine locations. GPS units are known for their accuracy, usually within 10 meters. They have also been used to measure the height of Mt. Everest, which has been recorded as 8850 meters above sea level, or 29,035 feet. So, the correct answer is option a.