Final answer:
If an approaching driver won't dim their high beams, the safest response is to slow down and look to the right side of the road to help maintain lane positioning.
Step-by-step explanation:
When facing an approaching driver who refuses to switch their high beams to low, the correct action to take is to slow down and look to the right side of the road. This helps to avoid being blinded by the high beams and losing sight of the road, which can lead to an accident. It also helps you to use the white line on the right side as a guide to maintain your lane position until you have safely passed the approaching vehicle with high beams.