All persons entering XYZ corporation are required to swipe their employee badge to get access to
the building. Which procedure, if implemented, is a stronger form of authentication than the current
one?

A.
Each employee inputs a unique user id and password on a terminal to unlock the door.

B.
Employees are each given a key to the building, which they should not share with others.

C.
A security guard is deployed at the building entrance to check the identity of each person
requesting entrance.

D.
The fingerprints of employees are scanned before they enter and are compared with those
recorded in a centralized database.