The correct answer is: A. Radio Detecting and Ranging
RADAR is an acronym for Radio Detection and Ranging. It is a system that uses radio waves to detect and locate objects. RADAR works by emitting a beam of radio waves and then measuring the time it takes for the waves to bounce off an object and return to the source. This information can be used to calculate
the distance to the object, its speed, and its direction of travel.RADAR is used in a variety of applications, including air traffic control, weather forecasting, and military surveillance. It is
also used in some consumer products, such as automatic door openers and garage door openers.Option B, Region Device and Ranging, is incorrect. RADAR is not a device that is used to detect regions.
Option C, Radio Detect and Rangs, is incorrect. The word “rangs” is not a word.
Option D, Radio Device and Ranging, is incorrect. The word “device” is not necessary in the acronym RADAR.