According to regulations, who must take reasonable precautions to avoid causing harmful interference?

The correct answer is that licensees must take reasonable precautions to avoid causing harmful interference. This refers to individuals or organizations that hold licenses to operate radio transmitting equipment or other communication devices. Licensees are obligated to ensure that their operations do not interfere with the communications of others, as stipulated by regulatory agencies like the Federal Communications Commission (FCC).

This duty is fundamental to maintaining an efficient communication environment, particularly in emergency situations where reliable communication is critical. Licensees are responsible for understanding the technical parameters of their equipment, adhering to operational guidelines, and proactively addressing any potential interference issues that may arise from their transmissions.

Other groups, such as emergency responders, public safety organizations, and telecommunication companies, although involved in communication, do not have the same regulatory obligations specifically tied to the licensing of frequencies. While they may take steps to mitigate interference as part of good practice, the regulatory responsibility primarily rests with licensees.