The voice VLAN feature has been enabled on a new Company Catalyst switch port. What is
the effect of this?

A.
The CoS is trusted for 802.1P or 802.1Q tagged traffic.

B.
PortFast is disabled on the port.

C.
Port Security is automatically enabled on a voice VLAN port.

D.
Untagged traffic is sent according to the default CoS priority of the port.

E.
None of the other alternatives apply

Explanation:
Default Voice VLAN Configuration:
The voice VLAN feature is disabled by default.
When the voice VLAN feature is enabled, all untagged traffic is sent according to the default
CoS priority of the port. The CoS value is not trusted for 802.1P or 802.1Q tagged traffic.
Reference:
http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_12c_ea1/
configuration/guide/swvoip.html