After validating the above, the customer is still having issues with network connectivity. What is the issue?

A customer is configuring an upstream disjoint Layer 2 network in a Cisco UCS domain. So far they have configured the following:

Fabric Interconnects are in switching mode.

There is symmetrical configuration for high availability.

There are no overlapping VLANs.

Each vNIC is communicating with one disjoint Layer 2 network.

After validating the above, the customer is still having issues with network connectivity. What is the issue?
A . Overlapping VLANs are allowed in a disjoint Layer 2 network.
B . The vNIC configuration is incorrect and must communicate with two or more disjoint layer 2 networks.
C . The fabric interconnect must be in end-host mode for a disjoint Layer 2 network.
D . Asymmetrical configuration for high availability needs to be configured.