INTERNATIONAL ONLY In addition to other required lights, which lights does a power-driven vessel pushing ahead or towing alongside display?

Correct Answer: Option C — Two white masthead lights in a vertical line

COLREG Rule 24(a)(i) requires a power-driven vessel when pushing ahead or towing alongside to exhibit two masthead lights in a vertical line. This configuration identifies the vessel as a towing vessel, distinguishing it from a single power-driven vessel which typically carries only one masthead light.