During Company.com planning session，Company.com presents the details of the current Network design. The network design serves four separate company facilities， each on as separate subnet. As part of a disaster recovery plan， the customer is evaluating the use of HACMP. Specifically， the have reviewed IPAT via IP aliasing and are questioning the number of IP subnets required. Given the customer’s current configuration，what is the recommended minimum number of IP subnets that would be required？（）