SONAR stands for?

SONAR stands for "Sound Navigation and Ranging." This term accurately describes the technology and its primary functions. SONAR systems utilize sound propagation to navigate, communicate, or detect objects under the surface of the water. By sending sound waves into the water and measuring the time it takes for the echoes to return, it can determine the distance to objects, making it essential for various applications in maritime navigation, underwater exploration, and even in military contexts.

The other options either simplify or incorrectly represent the full concept, omitting critical aspects involved in the navigation capabilities and the comprehensive use of sound in the ranging process. Thus, the complete phrase "Sound Navigation and Ranging" encapsulates both the navigation and distance-measuring functions that SONAR technology accomplishes.