What is the likely cause of this problem?

A customer wants to isolate a group of VMs within their Nutanix environment for security reasons. The customer creates a VM with two NICs to act as a firewall and installs the appropriate software and certificates.

However, no one from the outside can access the application.

What is the likely cause of this problem?
A . A shared volume group must be used by all isolated VMs
B . More than one NIC cannot be added to a VM
C . One of the NICs needs to be configured on the internal VLAN
D . Wireshark is installed on the NAT VM

Answer: C