Which of the following conditions require a licensed amateur radio operator to take specific steps to avoid harmful interference to other users or facilities?

Under FCC rules, amateur operators have specific obligations to avoid harmful interference in several unique scenarios. If operating within one mile of an FCC Monitoring Station, amateurs must protect the facility from interference so it can conduct its regulatory duties. When operating on a band where the Amateur Service is allocated on a secondary basis, amateurs must not cause harmful interference to, and must accept interference from, the primary users of that band. Finally, when transmitting spread spectrum emissions, amateurs must use specific precautions to avoid causing interference to other stations. Since all three of these specific conditions are explicitly covered by FCC Part 97 regulations, the correct choice is that all these conditions require licensed amateurs to take specific steps to avoid harmful interference.