Which of the following is not typically classified as a tangible asset?

Tangible assets are physical items that can be seen and touched, and they typically include things like real estate, inventory, and machinery. Patents, however, fall into a different category as they represent intangible assets. Intangible assets are non-physical items that have value due to the privileges or rights they convey, such as intellectual property, brand recognition, or copyrights. Unlike tangible assets, which can be easily quantified and assessed based on their physical presence, intangible assets are more difficult to value due to their non-physical nature. Therefore, patents are not classified as tangible assets, making this choice the correct answer in the context of the question.