Which scenario is addressed by Rule 15?

Answer: B — Crossing vessels

Rule 15 of the COLREGs specifically pertains to crossing situations between vessels. It establishes the responsibilities of vessels when they are on a collision course at sea, where one vessel is crossing in front of another. In such scenarios, the "stand-on" vessel is typically expected to maintain course and speed, while the "give-way" vessel must take action to avoid a collision. This rule is essential as it helps to clarify which vessel must maneuver to avoid potential collisions, thus enhancing navigational safety when vessels are crossing paths. The context defined by Rule 15 helps vessel operators understand their obligations when encountering other craft, enabling them to make informed decisions to prevent accidents on the water. This rule is particularly crucial in busy navigation channels, where the risk of collisions is higher due to multiple vessels operating in close proximity.