The correct answer is D. Patents.
Intangible assets are non-physical assets that have value because of the rights or privileges they convey to the owner. They include items such as patents, copyrights, trademarks, goodwill, and trade secrets.
Cash is a physical asset that has value because it can be used to purchase goods and services.
Investment in subsidiary companies is a financial asset that has value because it represents a claim on the assets and earnings of the subsidiary company.
Furniture is a physical asset that has value because it can be used to furnish a building or other structure.
Patents are intangible assets that have value because they give the owner the exclusive right to use an invention for a certain period of time.