Which option is a restriction of the unified ports on the Cisco UCS 6200 Series Fabric Interconnect
when connecting to the unified fabric network?

A.
Direct FC connections are not supported to Cisco MDS switches

B.
The FCoE or Fibre Channel port allocations must be contiguous on the 6200.

C.
10-G Fibre Channel ports only use SFP+ interfaces.

D.
vPC is not supported on the Ethernet ports.

Explanation:
When you configure the links between the Cisco UCS 2200 Series FEX and a Cisco UCS 6200 series
fabric interconnect in fabric port channel mode, the available VIF namespace on the adapter varies
depending on where the FEX uplinks are connected to the fabric interconnect ports.
Inside the 6248 fabric interconnect there are six sets of eight contiguous ports, with each set of ports
managed by a single chip. When uplinks are connected such that all of the uplinks from an FEX are
connected to a set of ports managed by a single chip, Cisco UCS Manager maximizes the number of
VIFs used in service profiles deployed on the blades in the chassis. If uplink connections from an IOM
are distributed across ports managed by separate chips, the VIF count is decreased.

http://www.cisco.com/c/en/us/td/docs/unified_computing/ucs/hw/6200-installguide/6200_HIG/6200_HIG_chapter_01.html