What is the significance of the "Caution" flag while boating?

The "Caution" flag is significant because it alerts boaters to the possibility of hazards or dangers in the water. This could include anything from submerged obstacles, strong currents, or areas where other vessels might be present. The flag serves as a warning to exercise increased vigilance and take necessary precautions while navigating in the area, promoting safety for all boaters.

In contrast, the other options indicate different meanings that do not correlate with the purpose of the caution flag. For example, a flag indicating a safe swimming area is used to designate places where it is safe for swimmers to be, while a signal that shows the end of the boating season or a fishing area does not pertain to immediate safety concerns like those denoted by a caution flag.