What signifies that a driver is under supervision in a GDL program?

In a Graduated Driver's License (GDL) program, supervision indicates that the novice driver is accompanied by an experienced driver who is responsible for ensuring safety and providing guidance. The presence of a supervisor in the front passenger seat, who holds a valid driver's license, is a clear sign that the new driver is being supervised during their driving practice. This arrangement helps the novice to learn driving skills in a controlled environment while also receiving immediate feedback from a qualified individual.

The other options do not have a direct correlation to the supervision requirement in the GDL program. For instance, displaying an instructor sticker, having specific fuel requirements, or using flags does not signify that a driver is under supervision in the same way that the presence of a licensed supervisor does. In this context, option A is the most accurate reflection of the supervision requirement in a GDL program.