What must the stand on vessel maintain unless the give way vessel is not taking action?

The correct answer is that the stand-on vessel must maintain course and speed. This is based on maritime navigation rules, particularly the "rules of the road" that govern the behavior of vessels at sea. The stand-on vessel is the boat that has the right of way in a crossing situation.

By maintaining its course and speed, the stand-on vessel allows the give-way vessel to determine the safest maneuver to avoid collision. If the give-way vessel is not taking action, the stand-on vessel must remain steady in its path to allow for a predictable movement, which is crucial for the safety of all vessels involved. This helps prevent confusion and potential accidents on the water.

Other choices, like maintaining distance and angle, or being cautious and ready, do not specifically relate to the established navigation rules regarding stand-on vessels. They might highlight good seamanship, but they do not emphasize the specific obligation of the stand-on vessel in a crossing situation, which focuses on course and speed.