A recent security audit revealed that there were indeed several occasions that the company's network was breached. After investigating, you discover that your IDS is not configured properly and theref

A true positive means the IDS correctly detected and alerted on a real attack, which is the opposite of what occurred since no alarms were triggered during confirmed breaches.

A false negative occurs when a security control fails to detect a genuine threat event. Since the network was actually breached but the misconfigured IDS never triggered alarms, it was silently missing real attacks - the definition of a false negative, where the system reports 'no threat' when a threat is present.

A false positive means the IDS generated an alert on benign activity that was not an attack, which is the inverse problem - over-alerting rather than under-alerting.

This choice is a duplicate of C and is incorrect for the same reason - a false positive is an erroneous alert on non-malicious activity, not a failure to detect real intrusions.