A datacenter director implements a new security measure in response to multiple equipment thefts from the datacenter. The new security measure requires people entering or leaving the datacenter to go

A mantrap is a physical security control consisting of a small room with two doors, where only one door can be open at a time. The requirement for multiple forms of authentication within this secure area to exit further enhances its function as a controlled access point designed to prevent unauthorized entry or exit and detect tailgating or piggybacking.

RFID cards are a form of authentication (something you have) but do not describe the physical structure of an "extra secure area" with two-door interlocking.

Defense in depth is a strategy that combines multiple layers of security controls; while a mantrap can be part of it, defense in depth itself is not a specific physical security measure.

Biometrics is a form of authentication (something you are) but does not describe the physical "extra secure area" with controlled entry and exit.