In what case can the lights on an oil rig be displayed outside the normal requirements?

The lights on an oil rig can be displayed outside the normal requirements from 15 minutes before sunset until sunrise to ensure visibility during times when natural light is insufficient. This specific period is critical as it is the transition into night, when navigation can become more hazardous due to reduced visibility. In these conditions, the display of lights is essential for ensuring that the oil rig is easily identifiable to approaching vessels, thereby enhancing safety.

While it might seem that options like maintenance or inclement weather could justify different lighting requirements, these situations do not specifically align with the established guidelines under the COLREGs (International Regulations for Preventing Collisions at Sea) regarding navigation lights. Normal lighting requirements take precedence, except during the defined twilight hours, ensuring that vessels can effectively navigate near potentially hazardous structures like oil rigs. Therefore, option B accurately reflects the COLREGs provisions about lighting for oil rigs in relation to changing light conditions.