How many grades of antifreeze are suitable for winterizing based on temperature?

The suitable number of grades of antifreeze for winterizing based on temperature is two. Antifreeze is typically formulated to protect against freezing at specific temperature thresholds, usually classified in two grades: one for milder winter conditions and one for more extreme cold. Each of these grades is designed to provide effective protection at different temperatures, enabling safer operation of the vehicle or equipment in varying winter climates.

Understanding the correct antifreeze grade is crucial for ensuring optimal performance and avoiding damage due to freezing, which can lead to engine block cracks and other serious issues. The other options suggest varying numbers of grades, which do not accurately reflect the common classifications used in antifreeze products.