Packet Filtering Firewall is responsible for filtering the packets based on the IP addresses (source and destination), source and destination port numbers and also the source and destination protocols.
These firewalls operate at the junctions such as switches and routers.
Packets that don't meet required criteria are dropped and they cannot further forwarded.
It is not fully secured and can be used by the malicious attackers.
So, option (c) is Correct.
Option (a), Application Layer Firewall is a firewall at the application level not at the packets level.So, option (a) is not the correct option.
Option (b), Stateful firewall is different and it is not the correct answer.
