An organization wants to define its physical perimeter. What primary device should be used to accomplish this objective if the organization's perimeter MUST cost-efficiently deter casual trespassers?

Fences eight or more feet high with three strands of barbed wire exceed the requirements for deterring casual trespassers and represent a higher-cost, more aggressive security posture typically reserved for high-security facilities rather than basic perimeter definition.

Fences three to four feet high with a turnstile are too low to effectively deter even casual trespassers, as this height is easily climbed or stepped over, making it insufficient as a physical deterrent.

Fences accompanied by patrolling security guards are significantly more expensive due to ongoing personnel costs, making this solution not cost-efficient for the stated objective of deterring casual trespassers.

Fences six to seven feet high with a painted gate represent the standard cost-efficient solution for deterring casual trespassers, as this height is difficult enough to climb to discourage opportunistic intrusion without the added expense of barbed wire or guards. The painted gate provides a clear, visible entry point that signals the boundary of the perimeter. This configuration meets the 'casual trespasser deterrence' threshold defined in physical security frameworks without over-engineering the solution.