Answer:
C. Implement a biometric reader at the datacenter entrance and require passage through a mantrap.
Step-by-step explanation:
The first step this installation should do is to limit access to only authorized persons. The safest way to do this is to use a biometric reader at the datacenter entrance, so in addition to just entering authorized persons, it would be possible to verify each individual's identity before allowing access to the server room and datacenter. The facility should also use a mantrap to separate safe areas from unsafe areas, so it can also limit access to the facility and decrease the chances of users tailgate behind other uses.