The correct option for preparing for winter driving in relation to antifreeze is: c) Ensuring it has a high enough freezing point.
Antifreeze is a liquid that lowers the freezing point of water, preventing it from freezing and damaging your car's engine. Checking the tire pressure, replacing your windshield wipers, and checking the battery voltage are all important tasks for winter driving, but they are not related to the antifreeze.
So, it's important to ensure that your antifreeze has a low enough freezing point to provide sufficient protection against freezing during winter conditions.