A company wants to ensure that only authorized devices can enter an environment.

The best answer is A. Access lists .

To ensure that only authorized devices can enter or connect to an environment, the organization needs a control that explicitly allows approved devices and denies unapproved ones. Access lists are used to define which devices, systems, or addresses are permitted access.

This can include allowlists based on:

device identifiers

MAC addresses

IP addresses

approved system entries

predefined access control rules

Why the other options are incorrect:

B. Remote connection This is a method of connecting, not a control that determines which devices are authorized.

C. Screened subnets A screened subnet helps separate public-facing systems from internal systems, but it does not directly ensure only authorized devices can enter.

D. Centralized proxy A proxy mediates traffic requests, but it is not the primary control for allowing only authorized devices into an environment.

From a Security+ perspective, restricting access to only approved devices is best aligned with allow/deny rules through access lists , so A is the strongest answer.