Final answer:
When making a right turn, the ground reference is the right edge of the roadway.
Step-by-step explanation:
The ground reference for a right turn is the right edge of the available roadway you are turning onto. When making a right turn, you should position your vehicle close to the right side of the roadway. This allows enough space for other vehicles to pass on the left and ensures that your turn is made safely. By using the right edge of the roadway as a reference point, you can maintain a proper position during the turn.