Answer:
The correct answer is letter "D": log file monitor.
Step-by-step explanation:
A log file is a file in which the processes taking place in a server or a network system are registered. The log file analysis used to be the most common way of obtaining information about a web page's visitors. The log file monitor is the system that controls the log files, also network devices from where the log file feed was obtained and other information recording tools or Intrusion Detection and Prevention Systems (IDPS).