While performing a site survey to document the existing environment before implementing a new HACMP cluster， it was discovered that a port filtering firewall was being used to protect the production system. The plan is to continue using the firewall and add a second firewall to avoid a single point of failure. Each node in the two-node cluster will have all of its network adapters connected to the firewalls， and all connections to the nodes will pass through these firewalls. What must be considered about HACMP in a firewall environment？（）

A. Firewalls are not supported in a HACMP environment.
B. HACMP uses only TCP/IP so firewalls are not relevant.
C. Specific ports must be open for HACMP communications.
Dynamic routing must be used to properly route packets in a firewall-protected environment.