If the Master of a US-flag towing vessel replaces any crew member with a non-US citizen, he/she must ensure that the __________.

Correct Answer: Option D — all of the above

46 U.S.C. § 8103 mandates that when employing non-US citizens on foreign voyages, the Master must ensure the replacement is qualified, the vessel is outside US jurisdiction, and the individual can effectively communicate with the crew. These safeguards maintain operational safety and regulatory compliance while addressing temporary manning shortages.