Final answer:
The Sussex Pledge included provisions for the safety of passenger and merchant ship passengers, but did not include unrestricted travel in the North Sea. The correct answer is that all ships could freely travel the North Sea was not part of the pledge.
Step-by-step explanation:
The Sussex Pledge was a promise made by the German government during World War I to limit its submarine warfare policy following the sinking of the French passenger ship Sussex in March of 1916. This pledge included several conditions, such as not targeting passenger ships and providing for the safety of merchant ship passengers and crew before sinking a merchant vessel, but it did not guarantee that all ships could freely travel the North Sea. The correct answer to the question is c. All ships could freely travel the North Sea, as this was not a condition of the Sussex Pledge.