An administrator decides to implement access control techniques to secure a datacenter. Which of the following would be the STRONGEST technique for the administrator to use?

Multifactor authentication combines two or more independent factors - something you know, something you have, and/or something you are - so compromising a single factor is not sufficient to gain access. This layered approach addresses the weaknesses of any single credential type and is recognized by NIST and industry standards as the strongest authentication mechanism. Unlike physical controls alone, MFA actively validates the identity of the person attempting access.

An RFID chip is a single-factor physical token that can be cloned, lost, or stolen, providing weaker protection than a multi-factor approach.

Cipher locks rely on a single PIN or combination code, which represents only one factor and can be observed, shared, or guessed.

Bollards are vehicle barriers designed to prevent ram-raid physical intrusions and do not authenticate or control individual personnel access.