Which of the following collision avoidance systems helps airplanes avoid colliding with each other?

The answer is TCAS (Traffic Collision Avoidance System) because it is specifically designed for airplanes to avoid colliding with each other. TCAS works by actively tracking the positions and altitudes of nearby aircraft through the use of transponders, and it provides timely and precise instructions to pilots on how to avoid potential collisions. This system operates independently from the air traffic control system, allowing aircraft to quickly respond to potential threats even in areas with limited or no radar coverage. TCAS helps enhance safety in the skies by providing pilots with a proactive tool to prevent mid-air collisions, making it the ideal collision avoidance system for airplanes.