Which of the following is a form of gate that allows one person to pass at a time?

A.
Biometric

B.
Man-trap

C.
Turnstile

D.
Fence

Explanation:
A turnstile is also called a baffle gate. It is a form of gate that allows one person to pass
at a time. Turnstile can also be made so as to
enforce one-way traffic of people, and in addition, it can restrict passage only to people who insert a
coin, a ticket, a pass, or similar. Thus, a
turnstile can be used in the case of paid access.
Answer option D is incorrect. A fence is a perimeter-defining device. It differentiates between those
locations that are under some specified

security protection and those that are not under any security protection. Fencing contains various
components, materials, and construction
methods. It also includes stripes painted on the ground, barbed wires, chain link fences, concrete
walls, and some invisible perimeters in
which laser, motion, and heat detectors are used.
Answer option A is incorrect. Biometrics is a method of authentication that uses physical
characteristics, such as fingerprints, scars, retinal
patterns, and other forms of biophysical qualities to identify a user. Nowadays, the usage of
biometric devices such as hand scanners and
retinal scanners is becoming more common in the business environment.
Answer option B is incorrect. A man-trap in modern physical security protocols refers to a small
space having two sets of interlocking doors
such that the first set of doors must close before the second set opens. Identification may be
required for each door, and possibly different
measures for each door. For example, a key may open the first door, but a personal identification
number entered on a number pad opens the
second. Other methods of opening doors include proximity cards or biometric devices such as
fingerprint readers or iris recognition scans.
“Man-traps” may be configured so that when an alarm is activated, all doors lock and trap the
suspect between the doors in the “dead-space”
or lock just one door to deny access to a secure space such as a data center or research lab.