Which organization maintains the central registry for seamen?

The correct answer is the National Seamen Board, as this organization is responsible for maintaining the central registry of seamen within the Philippines. The National Seamen Board plays a crucial role in the regulation and management of seafarers, ensuring that they are properly documented and that their rights and welfare are upheld while at sea.

The National Seamen Board is specifically tasked with the oversight of various issues related to the employment of seafarers, and part of its mandate includes maintaining accurate and up-to-date records of the individuals engaged in maritime employment. This central registry is essential for various purposes, including monitoring seafarer qualifications, providing necessary support services, and ensuring compliance with national and international maritime laws.

Other organizations mentioned serve different functions within the maritime sector but do not focus specifically on maintaining the central registry for seamen, which distinguishes the National Seamen Board as the appropriate choice for this question.