Saskatchewan Driver Education GDL Class 7 Learner Practice Test

The correct licence class that allows the operation of power units and semi trailers is Class 1. This option is correct because it is specifically designed for operating heavy combination vehicles, such as trucks with multiple trailers attached. The other options, Class 2, Class 4 and Class 5, do not have the same level of authorization and are meant for lighter or smaller vehicles. Class 2 is for buses, Class 4 is for small trucks and Class 5 is for passenger vehicles. Therefore, these options are incorrect as they do not meet the specific requirements for operating power units and semi trailers.