Which solution meets the requirement of ensuring staff members use both something they know and something they have as part of a physical access control scheme?

Access badges are an example of something you have, and PINs are an example of something you know. Combining the two is a common requirement to help prevent a lost badge from providing access to a secure facility. A security desk with a guard is more costly but can be more effective if the guards are well trained and diligent, but the requirement is properly met by the access badge and PIN.