Many Businesses Print Their Employees' Photographs on Building Passes, So

Many businesses print their employees' photographs on building passes, so that employees can be identified by security staff. This is notwithstanding the fact that facial images potentially qualify as biometric data under the GDPR. Why would such practice be permitted?

A) Because use of biometric data to confirm the unique identification of data subjects benefits from an exemption.
B) Because photographs qualify as biometric data only when they undergo a "specific technical processing".
C) Because employees are deemed to have given their explicit consent when they agree to be photographed by their employer.
D) Because photographic ID is a physical security measure which is "necessary for reasons of substantial public interest".