Final answer:
Connectors working at heights should use fall protection equipment when working 6 feet or more above lower levels, according to OSHA standards.
Step-by-step explanation:
The question is about the safety regulations about workers operating at heights, particularly in the context of construction or engineering. In the United States, the Occupational Safety and Health Administration (OSHA) typically mandates that workers who are working at heights of 6 feet (1.8 meters) or more above lower levels must be provided with and must use fall protection equipment.
Therefore, the correct option in this context is generally (a) 6 and 10 feet; however, specific job sites or local regulations may have different requirements. It's always best to consult the current local safety regulations or OSHA standards for the most accurate and up-to-date information.