The Hotel Flag indicates that:

The correct answer indicates that a Pilot is required onboard. This is a crucial signal in maritime operations, as it informs other vessels, as well as harbor authorities and pilots, that the ship needs a trained pilot to navigate safely through potentially tricky waters. The presence of a pilot is essential when dealing with port entries, especially in environments where local knowledge of tides, currents, and navigational hazards is critical. When a vessel displays a flag indicating the need for a pilot, it ensures that safe and efficient navigation can be achieved, reducing the risk of accidents or incidents in busy shipping areas.

The other choices, while they represent important messages in maritime communication, do not pertain to the situation of requiring a pilot. For example, a flag indicating that an incoming vessel requires assistance or that it is stopped might serve different safety or operational purposes, but they do not specifically signal the need for a pilot. Similarly, the flag for dangerous cargo serves the function of alerting others to proceed with caution due to safety concerns, which is a separate issue from the vessel's navigation needs.