Creating a VLAN for Wi-Fi-enabled environmental sensors is the most likely and appropriate action.
Security+ SY0-701 recommends network segmentation for IoT and sensor devices to reduce attack surface and limit lateral movement. A dedicated VLAN isolates sensors from critical systems while allowing controlled access to data collectors or management platforms.
Adding items to a risk register (A) documents risk but does not provide protection. Physically air gapping (C) contradicts the requirement for Wi-Fi connectivity. Configuring TLS 1.2 (D) is beneficial for data-in-transit protection but does not address network-level isolation and blast-radius reduction.
Thus, B: Create a VLAN for the sensors best aligns with secure design.