Exam 212-89 topic 1 question 20 discussion

A US Federal agency network was the target of a DoS attack that prevented and impaired the normal authorized functionality of the networks. According to agency's reporting timeframe guidelines, this incident should be reported within two (2) HOURS of discovery/detection if the successful attack is still ongoing and the agency is unable to successfully mitigate the activity. Which incident category of the US Federal Agency does this incident belong to?