To protect a computer or a server, a(n) ______ can be installed that would act as a barrier and inspect data being transmitted to or from the network.

A) ethernet
B) firewall
C) protocol
D) rootkit

A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. It acts as a barrier between the network and the internet to prevent unauthorized access and attacks. Firewalls inspect the data being transmitted and filter out anything that doesn't comply with the set rules. Ethernet and protocol are not security mechanisms, and a rootkit is a type of malware that exploits vulnerabilities in a system to gain unauthorized access.