Final answer:
The correct mnemonic phrase for navigation in the U.S. lateral system is "Red, Right, Returning," which advises vessels to keep red navigational aids on their right side when returning from sea. The correct option is A.
Step-by-step explanation:
The phrase "Red, Right, Returning" acts as a mnemonic aid for vessels to remember the correct course when navigating the lateral system of U.S. Aids to Navigation. This means that when a vessel is returning from sea, the red navigational aids (such as buoys and markers) should be on the right (starboard) side of the vessel to ensure the correct passage in the channel.
This rule helps to promote maritime safety by providing a consistent method for mariners to determine the safest path through waters where the lateral system is in use.
Hence, Option A is correct.