Radar, which stands for Radio Detection and Ranging, is a technology that is used to detect and locate distant objects. It works by emitting radio waves and then analyzing the reflected waves that bounce back from objects in its path. This technology has a wide range of applications, including aviation, defense, weather forecasting, and navigation.

Here are the key points explaining why option 'C' is the correct answer:

1. Principle of Radar: Radar works on the principle of emitting radio waves and then receiving the reflected waves. It measures the time it takes for the waves to travel to an object and back, and uses this information to calculate the distance to the object.

2. Detection and Location: Radar is primarily used for detecting and locating distant objects. It can detect objects such as airplanes, ships, cars, and weather phenomena like clouds and precipitation. By analyzing the reflected waves, radar systems can determine the position, speed, and direction of the detected objects.

3. Range and Accuracy: Radar systems are capable of detecting objects at long distances, ranging from a few meters to hundreds of kilometers. The accuracy of radar depends on various factors such as the frequency of the radio waves, the power of the radar system, and the size and shape of the objects being detected.

4. Applications: Radar has numerous applications in different fields. In aviation, radar is used for air traffic control, collision avoidance, and weather monitoring. In defense, radar is used for surveillance, target tracking, and missile guidance. In weather forecasting, radar helps in detecting and tracking storms and measuring precipitation. In navigation, radar aids in ship and boat navigation by detecting other vessels and obstacles.

In conclusion, radar is a technology that is primarily used to detect and locate distant objects. It works by emitting radio waves and analyzing the reflected waves. Its applications range from aviation and defense to weather forecasting and navigation. Therefore, option 'C' is the correct answer.