What is the characteristic of Four Mile Rock Light "1"?

The characteristic of Four Mile Rock Light "1" is identified as "Fl G 6s," which refers to a specific type of light signal used for navigation purposes. This notation indicates that the light emits a green flash every six seconds. The use of "Fl" denotes a flashing light, while the "G" specifies the color green, which is significant in maritime navigation to indicate safe passages or mark navigational aids.

Understanding this characteristic is critical for sailors and navigators who rely on various light signals to determine their location and avoid hazards. The consistent timing and color of the light help in distinguishing Four Mile Rock Light "1" from other navigational aids, facilitating safer maritime travel.

Other options represent different light characteristics, such as different colors, flash intervals, or patterns, which are used in various navigational contexts. However, for the specific identification of Four Mile Rock Light "1," the flashing green light every six seconds is the defining characteristic.