Which of the following is the MOST reliable form of single factor personal identification?

A.
Smart card

B.
Password

C.
Photo identification

D.
iris scan

Explanation:

Since no two irises are alike, identification and verification can be done with confidence. There is
no guarantee that a smart card is being used by the correct person since it can be shared, stolen
or lost and found. Passwords can be shared and, if written down, carry the risk of discovery. Photo
IDs can be forged or falsified.