The correct answer is B.
OBJ-1.4: The Windows Defender Firewall is a software-based firewall that is installed by default on Windows workstations. The Windows Defender firewall is used to prevent hackers and malicious software from gaining access to the workstation over the Internet or the local area network. Explicit allow refers to a security posture where the system will only allow an item to traverse the firewall if the traffic matches an existing rule. Implicit allow refers to a security posture where the system will allow all traffic to traverse the firewall unless there is a specific rule to prevent it.