Final answer:
The best option for cutting a ventilation hole in a roof is a carbide-tip blade due to its durability and sharpness retention, making it suitable for tough materials.
Step-by-step explanation:
The best saw blade for cutting a ventilation hole in a roof is (B) a carbide-tip blade. Carbide-tipped blades are known for their durability and longevity, particularly when cutting through tough materials such as roofing. These blades retain their sharpness over time and are less likely to wear down when compared to other types of blades. This makes them highly suitable for cutting through wood and composite materials often found in roofs.