In the context of calculating net effective permissions for a resource in AWS, IPTables firewall rule is not used. Net effective permissions in AWS are determined by evaluating various AWS-specific mechanisms such as IAM policies, permission boundaries, and service control policies (SCPs). IAM policies define what actions are allowed or denied for various AWS resources. Permission boundaries provide a way to delegate administration for IAM entities, setting the maximum permissions that an IAM entity can have. SCPs are part of AWS Organizations and allow for central control over the maximum available permissions for all accounts within an organization. IPTables, on the other hand, is a Linux-based application for setting up firewall rules on individual hosts and is not directly related to AWS resource permissions. Therefore, IPTables firewall rules are not considered when calculating net effective permissions in AWS, making option C the correct answer.