What is the purpose of transferring radio communications and control responsibility early?

Transferring radio communications and control responsibility early primarily serves the purpose of clearing the aircraft beyond the clearance limit before it reaches it. This early transfer allows the receiving facility to take over the responsibility for the aircraft's separation and sequencing, ensuring that the aircraft is appropriately managed as it approaches critical airspace areas or clearance limits such as altitude or airspace boundaries.

By doing so, air traffic control can better manage traffic flow, maintaining safety and efficiency as the aircraft transitions from one jurisdiction to another. This helps to mitigate the risk of potential conflicts or breaches of clearance limits as the aircraft continues its approach or transit, which is crucial in busy airspace environments.

While the other options address aspects of air traffic control, such as reducing congestion, preparing for landing, or verifying flight plans, they do not specifically capture the primary focus of transferring control early as it relates to ensuring the safety of clearance limits for the aircraft in question.