Implementing VLANs can provide which of the following?

VLANs (Virtual LANs) allow logical segmentation of a physical network, which can be used to separate control device traffic from other network services (A), improving security and performance.

Sandboxing (B) relates to application or OS memory isolation, not VLANs.

Separation of duties for guest OSes (C) is related to virtualization, not VLANs.

Preventing access to diagnostic ports (D) requires port security or access control, not VLAN segmentation alone.

GICSP highlights VLANs as a fundamental technique for network segmentation in ICS security architectures.