Packet filter can inspect packets up to the network layer of the OSI model. Choose the statement that is true of the upper four layers of the OSI model.

A.
The upper four layers are left examined and disallow packets into internal network on these layers.

B.
The upper four layers are left examined and Packet filter allows packets into internal network on these layers.

C.
The upper four layers are left unexamined and Packet filter allows packets into internal network on these layers.

D.
The packets are forced into lower three layers and hence, examined.

E.
The upper four layers are left unexamined and Packet filter disallows packets into internal network on these layers.