The relationship between current packets with the previous packets of the same session, Stateful inspection firewalls are able to grant a broader range of access for authorized users and activities and actively watch for and block unauthorized users and activities.
C. Stateful inspection
Explanation:
Basically packet filtering handles in gateways level at firewall. As Network administrator he or she keep monitoring the network packet, if any unauthorized user login is found on any session or same session it is consider as high risk.
These shows some illegal access to computer has be executed as immediate action network engineer has to see logs and their activities in firewall either if it invalid transaction immediately he has put filter of ip address or mac address possible.
Network administration he or she update firewall patches at regular intervals.