Final answer:
Maintaining radio transmission discipline is crucial for effective aviation communication and is managed by Air Traffic Control (ATC), who ensures clarity, security, and efficiency of radio communications.
Step-by-step explanation:
Maintaining radio transmission discipline over the radio net is a critical responsibility that ensures communications are clear, secure, and efficient, and is typically managed by those who are operationally in charge of the communications networks. In the context of air traffic and aviation, this responsibility falls on the C) Air traffic control (ATC). It's the job of ATC personnel to manage the communication traffic, prioritize messages, and ensure that all users of the radio frequency adhere to the proper protocols and procedures for effective communication.