The correct answer is D) After Naval Control of Shipping has been established, permission to sail must come from local naval authorities or consular officers. This is correct because once the Allied Naval Control of Shipping (NCS) has been established, the movement of merchant ships is closely controlled by local naval authorities or consular officers. They have the authority to grant or deny permission for ships to sail, to ensure the coordinated movement of vessels and the efficient use of shipping resources during times of emergency or conflict. The other options are incorrect because A) assumes all ships at sea will be controlled by a central authority, which is not necessarily the case, B) pertains to the control of US-flag ships only, and C) suggests the NCS organization of each nation will only serve their own ships, when in reality they coordinate the movement of all allied merchant vessels.