The customer has deployed C7960 phones with clients connected to them. What switch feature could be enabled to distinguish IP voice traffic from client data traffic?

Configuring Voice VLAN on a switch access port causes the switch to advertise the voice VLAN ID to the connected Cisco 7960 phone via CDP. The phone then 802.1Q-tags outbound voice RTP traffic with that VLAN, while the downstream PC traffic passes through the phone untagged - giving the switch a clear Layer 2 boundary to apply separate QoS, security, and routing policies to each traffic type.

QoS routing is a WAN routing technique for selecting paths based on traffic class, not a switch port feature for separating voice and data VLANs.

WME (Wi-Fi Multimedia Extensions, 802.11e) is a wireless QoS mechanism and is not applicable to wired switch port configurations.

Weighted Queuing is a QoS scheduling mechanism for managing egress queue priority and does not separate traffic into distinct VLANs.

QBSS (QoS Basic Service Set) is a wireless 802.11e load information element used by APs and is unrelated to wired switch port voice segmentation.