Question 370Navigation General

The correct answer is A) 3 white lights in a vertical line in the center of the span. This is the standard marking for the main navigational channel span of a multiple-span bridge at night, as per the U.S. Coast Guard's Navigation Rules and Regulations Handbook. The three vertically stacked white lights indicate the center of the primary navigational channel that vessels should use when passing through the bridge. The other options are incorrect because: B) a steady blue light is not a standard bridge span marking, C) a quick flashing red or green aid to navigation would mark a different type of obstruction or channel boundary, and D) a flashing green light is not the proper indication for the main navigational span.