Which proprietary protocol allows for conformity of VLANs across all Cisco switches?

A. CDP
B. VTP
C. 802.1X
D. ISL

B. VLAN Trunking Protocol allows for conformity of VLANs across all Cisco switches. The protocol uses a master-slave database with a revision control of +1. If the server is 5 and the clients are 4, they will update the database to the latest revision.