Final answer:
The best solution to block communication between endpoint PCs without additional resources is Configuring a host-based firewall. Host-based firewalls can control traffic and apply specific rules, enhancing security efficiently. so, option B is the correct answer.
Step-by-step explanation:
The student has asked for the best solution to improve their network security posture by blocking communication between endpoint PCs without requiring additional resources for data isolation. Blocking communication between endpoint PCs can significantly reduce the attack surface and potential for lateral movement within a network if an endpoint is compromised. Considering the options provided and the requirement to not use additional resources, the best solution would be B. Configuring a host-based firewall. By configuring a host-based firewall, each endpoint can control inbound and outbound network traffic based on an applied rule set. This does not require any additional hardware or significant changes to the existing network infrastructure. Moreover, host-based firewalls can be tailored specifically to the needs of each endpoint, providing a cost-effective and resource-efficient method to enhance security.