In security terms, which of the following qualifies as "something you have"?

The classification of "something you have" in security terms refers to a physical object that is possessed by an individual, which can be used for authentication purposes. An ID card fits this definition perfectly because it is a tangible item that can be carried and presented to verify identity.

In contrast, a user ID is a username or identifier that does not represent a physical item but rather an electronic credential used in combination with a password. A password itself is also a piece of information that does not qualify as a physical object, as it is a secret code created by the user. Lastly, a retina scan is a biometric identification method that measures physiological characteristics, which doesn't fall into the category of "something you have" but rather "something you are." Thus, the ID card stands out as the only option that qualifies as an asset one possesses for the purpose of identification and security.