The correct answer is C) required to maintain course and speed in a crossing situation but may take action to avoid collision. The International Regulations for Preventing Collisions at Sea (COLREGS) state that in a crossing situation, the stand-on vessel (the vessel that has the other on its starboard side) is required to maintain its course and speed, unless taking such action would lead to a collision. The stand-on vessel may take action to avoid the collision, but is not required to give way to the other vessel. This is in contrast to the give-way vessel, which must take early and substantial action to avoid the collision. The other options are incorrect because A) the stand-on vessel does not have absolute right-of-way, it must still take action to avoid a collision if necessary; B) the give-way vessel is required to sound the first passing signal in a meeting situation; and D) the stand-on vessel is not required to give way in a crossing situation, unless taking action is necessary to avoid a collision.