A security administrator is tackling issues related to authenticating users at a remote site. There have been a large number of security incidents that resulted from either tailgating or impersonation of authorized users with valid credentials. The security administrator has been told to implement multifactor authentication in order to control facility access. To secure access to the remote facility, which of the following could be implemented without increasing the amount of space required at the entrance?
A. MOTD challenge and PIN pad
B. Retina scanner and fingerprint reader
C. Voice recognition and one-time PIN token
D. One-time PIN token and proximity reader