Which of the following actions has the highest priority for air traffic controllers?

Separating two converging aircraft holds the highest priority for air traffic controllers because it is directly related to ensuring the safety of aircraft in flight. The primary objective of air traffic control is to prevent collisions between aircraft, which makes maintaining safe separation distances between them critical. When two aircraft are on converging paths, immediate action must be taken to ensure they do not come too close to one another, potentially resulting in a dangerous situation.

While actions such as relaying control information, clearing an aircraft to avoid significant weather, and providing flight updates are important for maintaining safe and efficient operations, they don't directly address the immediate and potentially life-threatening situation posed by converging aircraft. Safety takes precedence in air traffic control decision-making, prioritizing separation above other responsibilities.