The correct answer is B.
OBJ-4.4: Isolation involves removing an affected component from whatever larger environment it is a part of. This can be everything from removing a server from the network after it has been the target of a DoS attack, placing an application in a sandbox virtual machine (VM) outside of the host environments it usually runs on. Segmentation-based containment is a means of achieving the isolation of a host or group of hosts using network technologies and architecture. Segmentation uses VLANs, routing/subnets, and firewall ACLs to prevent a host or group of hosts from communicating outside the protected segment. Removal is not an industry term used but would be a synonym for isolation. Enumeration is defined as the process of extracting user names, machine names, network resources, shares, and services from a system. Isolating the attacker would only stop their direct two-way communication and control of the affected system. However, it would not be the strongest possible response since there could be malicious code still running on your victimized machine.