Which of the Following Describes Automatic Vehicle Location (AVL)

Which of the following describes automatic vehicle location (AVL) ?

A) Uses GPS tracking to track vehicles.
B) Use plastic or conductive polymers instead of silicon-based microchips, allowing them to be washed or exposed to water without damaging the chip.
C) A device that measures the acceleration (the rate of change of velocity) of an item and is used to track truck speeds or taxi cab speeds.
D) A satellite-based navigation system providing extremely accurate position, time, and speed information.