What is the reason that ProfiNET frames are discarded by default on Catalyst switches?
A . ProfiNET uses a nonstandard Ethernet frame format
B . The frames have an 802.1q tag with VLAN ID equal to 0 (zero)
C . Catalyst switches do not support ProfiNET traffic
D . A ProfiNET VLAN must be configured and enabled on a Catalyst switch
Answer: B