The correct answer is C. Air.
An asset is a resource with economic value that an individual, corporation, or country owns or controls with the expectation of economic benefit in the future.
A car is a vehicle that is used for transportation. It is a tangible asset that can be bought and sold.
A human life is not an asset because it is not a tangible object. It is a concept that refers to the existence of a person.
A house is a building that is used for shelter. It is a tangible asset that can be bought and sold.
Air is a substance that is essential for life. It is not a tangible object and cannot be bought or sold. Therefore, it is not an asset.