The correct answer is C) You must provide passage to the port of original engagement. This is correct because under U.S. Coast Guard regulations, as the Master of the vessel, you are responsible for repatriating the crew to the port where they were originally engaged, even if the vessel is sold in a foreign country after discharge of cargo. This requirement ensures that the crew can return to their point of origin and find employment on another U.S. vessel if desired. The other options are incorrect because: A) The crew cannot be employed on another U.S. vessel unless it is returning to the original port; B) Providing air transportation is not required, only passage to the original port; and D) There is always a requirement to repatriate the crew, regardless of the voyage duration.