A geopositioning device uses satellites to find the elevation at a given location. An engineer is testing four different devices, A, B, C, and D. To test the devices, the engineer brings each device to location at sea level, where the elevation is known to be exactly 0 meters. The engineer takes multiple readings on each device throughout the day. a) If you worked for a construction company and needed to purchase a geopositioning device to find the elevation at a building site, which device would you buy? Why?

b) Which device would be the worst to use? Explain.