After installing a new switch and connecting redundant uplinks to other switches, a LAN experiences a broadcast storm causing severe throughput problems. Which of the following is the MOST likely cause of the broadcast storm?

A. VLAN assignments on the new switch conflicted with existing VLAN assignments elsewhere on the network.
B. Spanning tree protocol was not operational on the LAN.
C. Incorrect trunk encapsulation was applied.
D. Port aggregation was incorrectly configured

Answer: B. Spanning tree protocol was not operational on the LAN.