On a 75-meter boat, which lights must be displayed?

For a 75-meter boat, the appropriate navigation lights required under the International Regulations for Preventing Collisions at Sea (COLREGS) includes running lights and two masthead lights. A vessel of this size is classified as a large ship and must adhere to specific lighting requirements to ensure visibility and safety in various conditions.

The running lights, which include port (red) and starboard (green) sidelights, as well as a white stern light, allow other vessels to determine the size, type, and direction of the boat. In addition, the two masthead lights, positioned vertically when viewed from the front, show that the vessel is a larger power-driven ship. These features are essential when navigating in crowded waterways or at night, as they clearly indicate the vessel's position and movement to other boats, thus helping in collision avoidance.

This combination of running lights and two masthead lights is a critical requirement for safety and compliance with maritime regulations for a vessel of this length. The other options mentioned do not meet the necessary legal requirements for a boat of this size, contributing to their inapplicability.