Which item is NOT part of a captain's responsibility?

A captain's responsibilities center around the safe and effective operation of the vessel. This includes supervising the crew onboard, which ensures that all operations run smoothly and that crew members perform their duties effectively. Setting the vessel's course is a critical navigational responsibility, as it involves determining the route to reach the intended destination safely while considering factors such as weather and water conditions. Additionally, ensuring adherence to safety protocols is paramount, as the captain must enforce safety measures to protect both the crew and the ship from potential hazards.

Conducting social events for the crew, while it may contribute to morale and team-building, does not fall within the core responsibilities that are vital for the safety and operation of the vessel. Therefore, it's not considered a fundamental duty of a captain, making it the correct answer in this context. This distinction helps reinforce the primary roles a captain must fulfill to ensure the vessel and crew operate effectively and safely.