How many skiers can a boat tow according to carrying capacity?

The correct answer states that a boat can tow as many skiers as are safe according to the Australian Builders Plate, which serves as an important regulatory guideline. The Builders Plate provides essential information about the vessel's carrying capacity, including the maximum number of persons or weights it can safely carry while in operation. This includes not just the driver and any passengers, but also the skiers being towed.

When considering the safety and stability of the vessel, it’s crucial that the total weight of the people being towed and those onboard does not exceed the recommended limits set by the Builders Plate. This approach helps to ensure the safety of everyone involved during water activities.

The other options suggest restrictions that do not align with the regulatory framework provided by the Builders Plate, which prioritizes safety overall rather than arbitrary limits on the number of towed skiers.