Step 1: Fireproof fibers must resist ignition and combustion at high temperature.
Step 2: Vegetable fibers (cotton, jute), animal fibers (wool, silk) and most man made fibers burn or melt under flame.
Step 3: Mineral based fibers such as asbestos and glass fiber are inorganic in composition, so they do not burn and are fireproof.
Answer: Mineral Based Fiber.