Final answer:
The most effective type of fire extinguisher to have near a machine shop with fine metal shavings is a Class D fire extinguisher, which is designed to extinguish fires involving combustible metals.
Step-by-step explanation:
The most effective type of fire extinguisher to have near a machine shop with fine metal shavings would be a Class D fire extinguisher. Class D fire extinguishers are specifically designed to extinguish fires involving combustible metals, such as magnesium, titanium, and sodium. These types of fire extinguishers use a special dry powder or sand to smother the fire and eliminate the oxygen fueling it.