Which feature must be enabled to eliminate the broadcasting of all unknown traffic to switches that are not participating in the specific VLAN?

Which feature must be enabled to eliminate the broadcasting of all unknown traffic to switches that are not participating in the specific VLAN?
A . VTP pruning
B . port-security
C . storm control
D . bpdguard

Answer: A

Explanation:

VTP ensures that all switches in the VTP domain are aware of all VLANs.

However, there are occasions when VTP can create unnecessary traffic. All unknown unicasts and broadcasts in a VLAN are flooded over the entire VLAN. All switches in the network receive all broadcasts, even in situations in which few users are connected in that VLAN. VTP pruning is a feature that you use in order to eliminate or prune this unnecessary traffic.

Reference: http://www.cisco.com/c/en/us/ support/docs/lan-switching/vtp/1055821.html#vtp_pruning