BOTH INTERNATIONAL & INLAND A vessel servicing a pipeline during the day shall display __________.

Correct Answer: Option C — three black shapes in a vertical line; the highest and lowest are balls, and the middle one is a diamond

Under COLREGS Rule 27(b), a vessel engaged in a-restricted-ability-to-maneuver operation such as servicing a submarine cable or pipeline must display three vertical shapes. The top and bottom shapes are black balls, and the middle shape is a black diamond to warn approaching traffic.