What authentication factor would be classified as "something you have"?

The correct classification of an authentication factor as "something you have" refers specifically to physical items or devices that an individual possesses and can utilize to verify their identity. PKI tokens, or Public Key Infrastructure tokens, fit this definition perfectly. They are tangible devices such as smart cards, USB tokens, or other hardware that generate or store cryptographic keys used for secure authentication.

In contrast, security questions, while they may be a component of multifactor authentication, rely on knowledge, making them an example of "something you know." Retina scans and biometric facial recognition are forms of biometric authentication, which fall under "something you are," since they rely on unique physical characteristics of the individual. Therefore, PKI tokens are the appropriate choice as they are physical items that support secure user identification and access control.