Asbestos is

Answer: Option B

Asbestos is a naturally occurring mineral fiber known for its excellent fire resistance and heat insulation properties.

It is classified as an incombustible and fireproof material, which is why it has been widely used in construction for insulation and fire protection.

Although asbestos is used in making corrugated roofing sheets, it itself is not a sheet but a material, so Option A is not correct.

Asbestos is not an organic substance; it is an inorganic mineral, so Option C is incorrect.

Therefore, the correct answer is an incombustible fireproof material.