On a bus whose seats are fitted with seat belts, it is compulsory for them to be used by...

A)all passengers.
B)only the driver.
C)only passengers over three years of age, as well as the driver.Correct
It is compulsory for the driver and passengers over three years of age to use the seat belts or other approved restraint systems fitted to the seats of vehicles designed to carry more than nine passengers, including the driver. Passengers must be informed of this obligation.